Disregard CV12 when UNNEST is detected in from_expression_element (#7211)

src/sqlfluff/rules/convention/CV12.py

@@ -108,9 +108,17 @@ class Rule_CV12(BaseRule):
                     no_recursive_seg_type=["select_statement"],
                 )
             )
+            encountered_function = self._get_from_expression_element_function(
+                join_table_reference
+            )
+            if encountered_function in ("UNNEST",):
+                # If UNNEST function is used, disregard lack of condition
+                continue
+
             encountered_references.add(
                 self._get_from_expression_element_alias(join_table_reference)
             )
+
             join_clause_keywords = [
                 seg for seg in join_clause.segments if seg.type == "keyword"
             ]
@@ -262,6 +270,32 @@ class Rule_CV12(BaseRule):
 
         return alias_str
 
+    @staticmethod
+    def _get_from_expression_element_function(from_expr_element: BaseSegment) -> str:
+        """Extract the function name from a from_expression_element if present."""
+
+        def get_segment_or_default(
+            segment: BaseSegment, child_type: str, default: BaseSegment
+        ) -> BaseSegment:
+            """Helper to safely get a child segment or return a default."""
+            child = segment.get_child(child_type)
+            return child if child else default
+
+        table_expr = get_segment_or_default(
+            from_expr_element, "table_expression", from_expr_element
+        )
+
+        if "function" not in table_expr.direct_descendant_type_set:
+            return ""
+
+        function = get_segment_or_default(table_expr, "function", table_expr)
+        function_name = get_segment_or_default(function, "function_name", table_expr)
+        function_id = get_segment_or_default(
+            function_name, "function_name_identifier", table_expr
+        )
+
+        return function_id.raw_upper
+
     @staticmethod
     def _is_where_clause_simplifable(where_clause: BaseSegment) -> bool:
         assert where_clause.is_type("where_clause")

test/fixtures/rules/std_rule_cases/CV12.yml

@@ -109,3 +109,26 @@ test_fail_join_with_bracketed_join:
       )
     WHERE
       bar.id = foo1.id;
+
+test_pass_left_join_unnest_where_aliased:
+  pass_str: |
+    SELECT
+      t.user_id,
+      unnested_value AS purchased_product
+    FROM
+      t
+    LEFT JOIN
+      UNNEST(t.purchases) AS unnested_value
+    WHERE
+      unnested_value = 'laptop'
+
+test_pass_left_join_unnest_where_unaliased:
+  pass_str: |
+    SELECT
+      t.user_id
+    FROM
+      t
+    LEFT JOIN
+      UNNEST(t.purchases)
+    WHERE
+      t.user_id != 1