diff --git a/CHANGELOG.md b/CHANGELOG.md
index f3675b7e..2443f51b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - Bug #275: Refactor `DMLQueryBuilder`, related with yiisoft/db#746 (@Tigrov)
 - Bug #278: Remove `RECURSIVE` expression from CTE queries (@Tigrov)
 - Bug #280: Fix type boolean (@terabytesoftw)
+- Bug #282: Fix `DDLQueryBuilder::alterColumn()` for columns with default null (@Tigrov)
 - Enh #283: Move methods from `Command` to `AbstractPdoCommand` class (@Tigrov)
 
 ## 1.0.1 July 24, 2023
diff --git a/src/DDLQueryBuilder.php b/src/DDLQueryBuilder.php
index 7430d31e..ad610ec0 100644
--- a/src/DDLQueryBuilder.php
+++ b/src/DDLQueryBuilder.php
@@ -53,8 +53,7 @@ public function addDefaultValue(string $table, string $name, string $column, mix
      */
     public function alterColumn(string $table, string $column, ColumnInterface|string $type): string
     {
-        $sqlAfter = [$this->dropConstraintsForColumn($table, $column, 'D')];
-
+        $sqlAfter = [];
         $columnName = $this->quoter->quoteColumnName($column);
         $tableName = $this->quoter->quoteTableName($table);
         $constraintBase = preg_replace('/[^a-z0-9_]/i', '', $table . '_' . $column);
@@ -85,11 +84,11 @@ public function alterColumn(string $table, string $column, ColumnInterface|strin
             }
         }
 
-        return 'ALTER TABLE ' . $tableName
-            . ' ALTER COLUMN '
-            . $columnName . ' '
-            . $this->queryBuilder->getColumnType($type) . "\n"
-            . implode("\n", $sqlAfter);
+        return implode("\n", [
+            $this->dropConstraintsForColumn($table, $column, 'D'),
+            "ALTER TABLE $tableName ALTER COLUMN $columnName {$this->queryBuilder->getColumnType($type)}",
+            ...$sqlAfter,
+        ]);
     }
 
     /**
diff --git a/tests/CommandTest.php b/tests/CommandTest.php
index 2c1896c4..5ce86c4c 100644
--- a/tests/CommandTest.php
+++ b/tests/CommandTest.php
@@ -12,6 +12,7 @@
 use Yiisoft\Db\Exception\InvalidConfigException;
 use Yiisoft\Db\Exception\NotSupportedException;
 use Yiisoft\Db\Expression\Expression;
+use Yiisoft\Db\Mssql\Column;
 use Yiisoft\Db\Mssql\Connection;
 use Yiisoft\Db\Mssql\Dsn;
 use Yiisoft\Db\Mssql\Driver;
@@ -353,4 +354,27 @@ public function testShowDatabases(): void
         $this->assertSame('sqlsrv:Server=localhost,1433;', $db->getDriver()->getDsn());
         $this->assertSame(['yiitest'], $command->showDatabases());
     }
+
+    /** @link https://github.com/yiisoft/db-migration/issues/11 */
+    public function testAlterColumnWithDefaultNull()
+    {
+        $db = $this->getConnection();
+        $command = $db->createCommand();
+
+        if ($db->getTableSchema('column_with_constraint', true) !== null) {
+            $command->dropTable('column_with_constraint')->execute();
+        }
+
+        $command->createTable('column_with_constraint', ['id' => 'pk'])->execute();
+        $command->addColumn('column_with_constraint', 'field', (new Column('integer'))->null()->asString())->execute();
+        $command->alterColumn('column_with_constraint', 'field', (new Column('string', 40))->notNull()->asString())->execute();
+
+        $fieldCol = $db->getTableSchema('column_with_constraint', true)->getColumn('field');
+
+        $this->assertFalse($fieldCol->isAllowNull());
+        $this->assertNull($fieldCol->getDefaultValue());
+        $this->assertSame('nvarchar(40)', $fieldCol->getDbType());
+
+        $command->dropTable('column_with_constraint');
+    }
 }
diff --git a/tests/QueryBuilderTest.php b/tests/QueryBuilderTest.php
index 1591f9c4..cf1a397b 100644
--- a/tests/QueryBuilderTest.php
+++ b/tests/QueryBuilderTest.php
@@ -602,53 +602,57 @@ public function testAlterColumn(): void
 
         $qb = $db->getQueryBuilder();
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] varchar(255)
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] varchar(255)
+            SQL;
         $sql = $qb->alterColumn('foo1', 'bar', 'varchar(255)');
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255) NOT NULL
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255) NOT NULL
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -656,29 +660,31 @@ public function testAlterColumn(): void
         );
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255)
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [CK_foo1_bar] CHECK (LEN(bar) > 5)";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255)
+            ALTER TABLE [foo1] ADD CONSTRAINT [CK_foo1_bar] CHECK (LEN(bar) > 5)
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -686,29 +692,31 @@ public function testAlterColumn(): void
         );
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255)
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT '' FOR [bar]";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255)
+            ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT '' FOR [bar]
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -716,29 +724,31 @@ public function testAlterColumn(): void
         );
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255)
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT 'AbCdE' FOR [bar]";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(255)
+            ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT 'AbCdE' FOR [bar]
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -746,29 +756,31 @@ public function testAlterColumn(): void
         );
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] datetime
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT CURRENT_TIMESTAMP FOR [bar]";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] datetime
+            ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT CURRENT_TIMESTAMP FOR [bar]
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -776,29 +788,31 @@ public function testAlterColumn(): void
         );
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(30)
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [UQ_foo1_bar] UNIQUE ([bar])";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] nvarchar(30)
+            ALTER TABLE [foo1] ADD CONSTRAINT [UQ_foo1_bar] UNIQUE ([bar])
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -1007,29 +1021,31 @@ public function testAlterColumnWithNull(): void
     {
         $qb = $this->getConnection()->getQueryBuilder();
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] int NULL
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT NULL FOR [bar]";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] int NULL
+            ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT NULL FOR [bar]
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -1037,29 +1053,31 @@ public function testAlterColumnWithNull(): void
         );
         $this->assertEquals($expected, $sql);
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] int NULL
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT NULL FOR [bar]";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] int NULL
+            ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT NULL FOR [bar]
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',
@@ -1076,29 +1094,31 @@ public function testAlterColumnWithExpression(): void
     {
         $qb = $this->getConnection()->getQueryBuilder();
 
-        $expected = "ALTER TABLE [foo1] ALTER COLUMN [bar] int NULL
-DECLARE @tableName VARCHAR(MAX) = '[foo1]'
-DECLARE @columnName VARCHAR(MAX) = 'bar'
-WHILE 1=1 BEGIN
-    DECLARE @constraintName NVARCHAR(128)
-    SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
-        FROM (
-            SELECT sc.[constid] object_id
-            FROM [sys].[sysconstraints] sc
-            JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
-            WHERE sc.[id] = OBJECT_ID(@tableName)
-            UNION
-            SELECT object_id(i.[name]) FROM [sys].[indexes] i
-            JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
-            JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
-            WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
-        ) cons
-        JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
-         WHERE so.[type]='D')
-    IF @constraintName IS NULL BREAK
-    EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
-END
-ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT CAST(GETDATE() AS INT) FOR [bar]";
+        $expected = <<<SQL
+            DECLARE @tableName VARCHAR(MAX) = '[foo1]'
+            DECLARE @columnName VARCHAR(MAX) = 'bar'
+            WHILE 1=1 BEGIN
+                DECLARE @constraintName NVARCHAR(128)
+                SET @constraintName = (SELECT TOP 1 OBJECT_NAME(cons.[object_id])
+                    FROM (
+                        SELECT sc.[constid] object_id
+                        FROM [sys].[sysconstraints] sc
+                        JOIN [sys].[columns] c ON c.[object_id]=sc.[id] AND c.[column_id]=sc.[colid] AND c.[name]=@columnName
+                        WHERE sc.[id] = OBJECT_ID(@tableName)
+                        UNION
+                        SELECT object_id(i.[name]) FROM [sys].[indexes] i
+                        JOIN [sys].[columns] c ON c.[object_id]=i.[object_id] AND c.[name]=@columnName
+                        JOIN [sys].[index_columns] ic ON ic.[object_id]=i.[object_id] AND i.[index_id]=ic.[index_id] AND c.[column_id]=ic.[column_id]
+                        WHERE i.[is_unique_constraint]=1 and i.[object_id]=OBJECT_ID(@tableName)
+                    ) cons
+                    JOIN [sys].[objects] so ON so.[object_id]=cons.[object_id]
+                     WHERE so.[type]='D')
+                IF @constraintName IS NULL BREAK
+                EXEC (N'ALTER TABLE ' + @tableName + ' DROP CONSTRAINT [' + @constraintName + ']')
+            END
+            ALTER TABLE [foo1] ALTER COLUMN [bar] int NULL
+            ALTER TABLE [foo1] ADD CONSTRAINT [DF_foo1_bar] DEFAULT CAST(GETDATE() AS INT) FOR [bar]
+            SQL;
         $sql = $qb->alterColumn(
             'foo1',
             'bar',