Added sql() and show() convenience method to QueryBuilder

Signed-off-by: Christian Molina <[email protected]>

python/deltalake/query.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import logging
 import warnings
 from typing import List
 
@@ -9,6 +10,8 @@
 from deltalake.table import DeltaTable
 from deltalake.warnings import ExperimentalWarning
 
+logger = logging.getLogger(__name__)
+
 
 class QueryBuilder:
     """
@@ -47,9 +50,9 @@ def register(self, table_name: str, delta_table: DeltaTable) -> QueryBuilder:
         )
         return self
 
-    def execute(self, sql: str) -> List[pyarrow.RecordBatch]:
+    def execute(self, sql: str) -> QueryResult:
         """
-        Execute the query and return a list of record batches
+        Prepares the sql query to be executed.
 
         For example:
 
@@ -59,6 +62,61 @@ def execute(self, sql: str) -> List[pyarrow.RecordBatch]:
         >>> dt = DeltaTable.create(table_uri=tmp, schema=pa.schema([pa.field('name', pa.string())]))
         >>> qb = QueryBuilder().register('test', dt)
         >>> results = qb.execute('SELECT * FROM test')
+        >>> assert isinstance(results, QueryResult)
+        """
+        return QueryResult(self._query_builder, sql)
+
+    def sql(self, sql: str) -> QueryResult:
+        """
+        Convenience method for `execute()` method.
+
+        For example:
+
+        >>> tmp = getfixture('tmp_path')
+        >>> import pyarrow as pa
+        >>> from deltalake import DeltaTable, QueryBuilder
+        >>> dt = DeltaTable.create(table_uri=tmp, schema=pa.schema([pa.field('name', pa.string())]))
+        >>> qb = QueryBuilder().register('test', dt)
+        >>> query = 'SELECT * FROM test'
+        >>> assert qb.execute(query).fetchall() == qb.sql(query).fetchall()
+        """
+        return self.execute(sql)
+
+
+class QueryResult:
+    def __init__(self, query_builder: PyQueryBuilder, sql: str):
+        self._query_builder = query_builder
+        self._sql_query = sql
+
+    def show(self) -> None:
+        """
+        Execute the query and prints the output in the console.
+
+        For example:
+
+        >>> tmp = getfixture('tmp_path')
+        >>> import pyarrow as pa
+        >>> from deltalake import DeltaTable, QueryBuilder
+        >>> dt = DeltaTable.create(table_uri=tmp, schema=pa.schema([pa.field('name', pa.string())]))
+        >>> qb = QueryBuilder().register('test', dt)
+        >>> results = qb.execute('SELECT * FROM test').show()
+        """
+        records = self.fetchall()
+        if len(records) > 0:
+            print(pyarrow.Table.from_batches(records))
+        else:
+            logger.info("The executed query contains no records.")
+
+    def fetchall(self) -> List[pyarrow.RecordBatch]:
+        """
+        Execute the query and return a list of record batches.
+
+        >>> tmp = getfixture('tmp_path')
+        >>> import pyarrow as pa
+        >>> from deltalake import DeltaTable, QueryBuilder
+        >>> dt = DeltaTable.create(table_uri=tmp, schema=pa.schema([pa.field('name', pa.string())]))
+        >>> qb = QueryBuilder().register('test', dt)
+        >>> results = qb.execute('SELECT * FROM test').fetchall()
         >>> assert results is not None
         """
-        return self._query_builder.execute(sql)
+        return self._query_builder.execute(self._sql_query)

python/tests/test_table_read.py

@@ -1,3 +1,4 @@
+import logging
 import os
 import tempfile
 from datetime import date, datetime, timezone
@@ -958,11 +959,14 @@ def test_read_query_builder():
         "month": ["4", "12", "12", "12"],
         "day": ["5", "4", "20", "20"],
     }
-    actual = pa.Table.from_batches(
-        QueryBuilder()
-        .register("tbl", dt)
-        .execute("SELECT * FROM tbl WHERE year >= 2021 ORDER BY value")
-    ).to_pydict()
+
+    qb = QueryBuilder().register("tbl", dt)
+    query = "SELECT * FROM tbl WHERE year >= 2021 ORDER BY value"
+
+    actual = pa.Table.from_batches(qb.execute(query).fetchall()).to_pydict()
+    assert expected == actual
+
+    actual = pa.Table.from_batches(qb.sql(query).fetchall()).to_pydict()
     assert expected == actual
 
 
@@ -998,5 +1002,22 @@ def test_read_query_builder_join_multiple_tables(tmp_path):
             ORDER BY tbl1.date
             """
         )
+        .fetchall()
     ).to_pydict()
     assert expected == actual
+
+
+def test_read_query_builder_show_output(capsys, caplog):
+    table_path = "../crates/test/tests/data/delta-0.8.0-partitioned"
+    dt = DeltaTable(table_path)
+    logging.getLogger("deltalake").setLevel(logging.INFO)
+
+    qb = QueryBuilder().register("tbl", dt)
+    query = "SELECT * FROM tbl WHERE year >= 2021 ORDER BY value"
+    qb.execute(query).show()
+    assert capsys.readouterr().out.strip() != ""
+
+    query = "SELECT * FROM tbl WHERE year >= 9999"
+    qb.execute(query).show()
+    assert "query contains no records" in caplog.text
+    assert capsys.readouterr().out.strip() == ""