[fix] escape parameter placeholder '?' by double question mark '??' J…

…etBrains#891

exposed-core/src/main/kotlin/org/jetbrains/exposed/sql/statements/Statement.kt

@@ -7,7 +7,7 @@ import org.jetbrains.exposed.sql.Transaction
 import org.jetbrains.exposed.sql.statements.api.PreparedStatementApi
 import java.sql.ResultSet
 import java.sql.SQLException
-import java.util.*
+import java.util.Stack
 
 internal object DefaultValueMarker {
     override fun toString(): String = "DEFAULT"
@@ -127,12 +127,13 @@ fun StatementContext.expandArgs(transaction: Transaction): String {
         val quoteStack = Stack<Char>()
         var lastPos = 0
 
-        for (i in sql.indices) {
+        var i = -1
+        while (++i < sql.length) {
             val char = sql[i]
             when {
                 char == '?' && quoteStack.isEmpty() -> {
                     if (sql.getOrNull(i + 1) == '?') {
-                        i.inc()
+                        i++
                         continue
                     }
                     append(sql.substring(lastPos, i))

exposed-tests/src/test/kotlin/org/jetbrains/exposed/sql/tests/shared/StatementTest.kt

@@ -0,0 +1,50 @@
+package org.jetbrains.exposed.sql.tests.shared
+
+import org.jetbrains.exposed.dao.id.IntIdTable
+import org.jetbrains.exposed.sql.ComplexExpression
+import org.jetbrains.exposed.sql.Expression
+import org.jetbrains.exposed.sql.Op
+import org.jetbrains.exposed.sql.QueryBuilder
+import org.jetbrains.exposed.sql.tests.DatabaseTestsBase
+import kotlin.test.Test
+
+class StatementTest : DatabaseTestsBase() {
+    @Test
+    fun `query with double question`() {
+        val table = object : IntIdTable("test_mod_on_pk") {
+            val otherColumn = short("other")
+        }
+
+        open class SubQueryComplex<T>(
+            private val operator: String,
+            private val expr: Expression<T>,
+            private val expr2: Expression<T>,
+        ) : Op<Boolean>(), ComplexExpression {
+            override fun toQueryBuilder(queryBuilder: QueryBuilder): Unit = queryBuilder {
+                +expr
+                +" "
+                +operator
+                +" ("
+                +expr2
+                +")"
+            }
+        }
+
+        withTables(table) {
+            val actual = table
+                .select(table.otherColumn)
+                .where {
+                    SubQueryComplex(
+                        "??",
+                        table.id,
+                        table.id
+                    )
+                }
+                .prepareSQL(this, false)
+            assertEquals(
+                "SELECT TEST_MOD_ON_PK.OTHER FROM TEST_MOD_ON_PK WHERE TEST_MOD_ON_PK.ID ?? (TEST_MOD_ON_PK.ID)".lowercase(),
+                actual.lowercase()
+            )
+        }
+    }
+}