fix: subquery alias and column qualifier case inconsistency (#514)

sqllineage/core/models.py

@@ -147,7 +147,15 @@ def __init__(self, name: str, **kwargs):
         """
         self._parent: Set[Union[Path, Table, SubQuery]] = set()
         self.raw_name = escape_identifier_name(name)
-        self.source_columns = kwargs.pop("source_columns", ((self.raw_name, None),))
+        self.source_columns = (
+            (
+                escape_identifier_name(raw_name),
+                escape_identifier_name(qualifier) if qualifier is not None else None,
+            )
+            for raw_name, qualifier in kwargs.pop(
+                "source_columns", ((self.raw_name, None),)
+            )
+        )
 
     def __str__(self):
         return (

sqllineage/core/parser/__init__.py

@@ -25,8 +25,7 @@ def end_of_query_cleanup(self, holder: SubQueryLineageHolder) -> None:
                 if len(holder.write) > 1:
                     raise SQLLineageException
                 tgt_tbl = list(holder.write)[0]
-                for idx in range(len(col_grp)):
-                    tgt_col = col_grp[idx]
+                for idx, tgt_col in enumerate(col_grp):
                     tgt_col.parent = tgt_tbl
                     for src_col in tgt_col.to_source_columns(
                         self.get_alias_mapping_from_table_group(tbl_grp, holder)

tests/sql/column/test_column_select_column.py

@@ -173,3 +173,19 @@ def test_comment_after_column_comma_last():
             ),
         ],
     )
+
+
+def test_select_column_name_case_insensitive():
+    sql = """INSERT INTO tab1
+SELECT col1,
+COL1
+FROM tab2"""
+    assert_column_lineage_equal(
+        sql,
+        [
+            (
+                ColumnQualifierTuple("col1", "tab2"),
+                ColumnQualifierTuple("col1", "tab1"),
+            )
+        ],
+    )

tests/sql/column/test_column_select_from_subquery.py

@@ -109,3 +109,20 @@ def test_window_function_in_subquery():
             (ColumnQualifierTuple("col2", "tab2"), ColumnQualifierTuple("rn", "tab1")),
         ],
     )
+
+
+def test_select_column_in_subquery_alias_and_qualifier_case_insensitive():
+    sql = """INSERT INTO tab1
+SELECT DT.col1
+FROM (SELECT col1 FROM tab2) dt"""
+    assert_column_lineage_equal(
+        sql,
+        [(ColumnQualifierTuple("col1", "tab2"), ColumnQualifierTuple("col1", "tab1"))],
+    )
+    sql = """INSERT INTO tab1
+SELECT dt.col1
+FROM (SELECT col1 FROM tab2) DT"""
+    assert_column_lineage_equal(
+        sql,
+        [(ColumnQualifierTuple("col1", "tab2"), ColumnQualifierTuple("col1", "tab1"))],
+    )