Merging upstream version 11.3.0.

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

2 files changed, 23 insertions, 7 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):
diff --git a/sqlglot/optimizer/pushdown_projections.py b/sqlglot/optimizer/pushdown_projections.py
index 3f360f9..07a1b70 100644
--- a/sqlglot/optimizer/pushdown_projections.py
+++ b/sqlglot/optimizer/pushdown_projections.py
@@ -13,7 +13,7 @@ SELECT_ALL = object()
 DEFAULT_SELECTION = lambda: alias("1", "_")
 
 
-def pushdown_projections(expression, schema=None):
+def pushdown_projections(expression, schema=None, remove_unused_selections=True):
     """
     Rewrite sqlglot AST to remove unused columns projections.
 
@@ -26,6 +26,7 @@ def pushdown_projections(expression, schema=None):
 
     Args:
         expression (sqlglot.Expression): expression to optimize
+        remove_unused_selections (bool): remove selects that are unused
     Returns:
         sqlglot.Expression: optimized expression
     """
@@ -57,7 +58,8 @@ def pushdown_projections(expression, schema=None):
                 ]
 
         if isinstance(scope.expression, exp.Select):
-            _remove_unused_selections(scope, parent_selections, schema)
+            if remove_unused_selections:
+                _remove_unused_selections(scope, parent_selections, schema)
 
             # Group columns by source name
             selects = defaultdict(set)