Merging upstream version 11.3.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 19 insertions, 5 deletions

diff --git a/sqlglot/optimizer/merge_subqueries.py b/sqlglot/optimizer/merge_subqueries.py
index 16aaf17..70172f4 100644
--- a/sqlglot/optimizer/merge_subqueries.py
+++ b/sqlglot/optimizer/merge_subqueries.py
@@ -314,13 +314,27 @@ def _merge_where(outer_scope, inner_scope, from_or_join):
     if not where or not where.this:
         return
 
+    expression = outer_scope.expression
+
     if isinstance(from_or_join, exp.Join):
         # Merge predicates from an outer join to the ON clause
-        from_or_join.on(where.this, copy=False)
-        from_or_join.set("on", simplify(from_or_join.args.get("on")))
-    else:
-        outer_scope.expression.where(where.this, copy=False)
-        outer_scope.expression.set("where", simplify(outer_scope.expression.args.get("where")))
+        # if it only has columns that are already joined
+        from_ = expression.args.get("from")
+        sources = {table.alias_or_name for table in from_.expressions} if from_ else {}
+
+        for join in expression.args["joins"]:
+            source = join.alias_or_name
+            sources.add(source)
+            if source == from_or_join.alias_or_name:
+                break
+
+        if set(exp.column_table_names(where.this)) <= sources:
+            from_or_join.on(where.this, copy=False)
+            from_or_join.set("on", simplify(from_or_join.args.get("on")))
+            return
+
+    expression.where(where.this, copy=False)
+    expression.set("where", simplify(expression.args.get("where")))
 
 
 def _merge_order(outer_scope, inner_scope):