Merging upstream version 20.11.0.

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

1 files changed, 25 insertions, 6 deletions

diff --git a/sqlglot/optimizer/qualify_tables.py b/sqlglot/optimizer/qualify_tables.py
index e0fe641..d460e81 100644
--- a/sqlglot/optimizer/qualify_tables.py
+++ b/sqlglot/optimizer/qualify_tables.py
@@ -4,12 +4,14 @@ import itertools
 import typing as t
 
 from sqlglot import alias, exp
-from sqlglot._typing import E
 from sqlglot.dialects.dialect import DialectType
 from sqlglot.helper import csv_reader, name_sequence
 from sqlglot.optimizer.scope import Scope, traverse_scope
 from sqlglot.schema import Schema
 
+if t.TYPE_CHECKING:
+    from sqlglot._typing import E
+
 
 def qualify_tables(
     expression: E,
@@ -46,6 +48,18 @@ def qualify_tables(
     db = exp.parse_identifier(db, dialect=dialect) if db else None
     catalog = exp.parse_identifier(catalog, dialect=dialect) if catalog else None
 
+    def _qualify(table: exp.Table) -> None:
+        if isinstance(table.this, exp.Identifier):
+            if not table.args.get("db"):
+                table.set("db", db)
+            if not table.args.get("catalog") and table.args.get("db"):
+                table.set("catalog", catalog)
+
+    if not isinstance(expression, exp.Subqueryable):
+        for node, *_ in expression.walk(prune=lambda n, *_: isinstance(n, exp.Unionable)):
+            if isinstance(node, exp.Table):
+                _qualify(node)
+
     for scope in traverse_scope(expression):
         for derived_table in itertools.chain(scope.ctes, scope.derived_tables):
             if isinstance(derived_table, exp.Subquery):
@@ -66,11 +80,7 @@ def qualify_tables(
 
         for name, source in scope.sources.items():
             if isinstance(source, exp.Table):
-                if isinstance(source.this, exp.Identifier):
-                    if not source.args.get("db"):
-                        source.set("db", db)
-                    if not source.args.get("catalog") and source.args.get("db"):
-                        source.set("catalog", catalog)
+                _qualify(source)
 
                 pivots = pivots = source.args.get("pivots")
                 if not source.alias:
@@ -107,5 +117,14 @@ def qualify_tables(
                 if isinstance(udtf, exp.Values) and not table_alias.columns:
                     for i, e in enumerate(udtf.expressions[0].expressions):
                         table_alias.append("columns", exp.to_identifier(f"_col_{i}"))
+            else:
+                for node, parent, _ in scope.walk():
+                    if (
+                        isinstance(node, exp.Table)
+                        and not node.alias
+                        and isinstance(parent, (exp.From, exp.Join))
+                    ):
+                        # Mutates the table by attaching an alias to it
+                        alias(node, node.name, copy=False, table=True)
 
     return expression