From e34481915cf26cd0aa130269b651196c324c5317 Mon Sep 17 00:00:00 2001
From: Andrew Werner <ajwerner@cockroachlabs.com>
Date: Wed, 9 Dec 2020 13:49:56 -0500
Subject: [PATCH] sql: fix bug in SHOW TABLES FROM <db> hiding non-public
 tables

The name resolution logic was hiding tables from schemas other than `public`
when using an explicit database name in `SHOW TABLES`.

Release note (bug fix): Fixed a bug whereby tables in schemas other than
"public" would not be displayed when running `SHOW TABLES FROM <db>`.
---
 pkg/sql/delegate/show_tables.go              | 12 +++++-
 pkg/sql/logictest/testdata/logic_test/schema | 42 ++++++++++++++++++++
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/pkg/sql/delegate/show_tables.go b/pkg/sql/delegate/show_tables.go
index a5a085c16c4e..2d9cd58a826c 100644
--- a/pkg/sql/delegate/show_tables.go
+++ b/pkg/sql/delegate/show_tables.go
@@ -29,9 +29,17 @@ func (d *delegator) delegateShowTables(n *tree.ShowTables) (tree.Statement, erro
 	if err != nil {
 		return nil, err
 	}
-
+	// If we're resolved a one-part name into <db>.public (which is the behavior
+	// of ResolveSchema, not for any obviously good reason), rework the resolved
+	// name to have an explicit catalog but no explicit schema. This would arise
+	// when doing SHOW TABLES FROM <db>. Without this logic, we would not show the
+	// tables from other schemas than public.
+	if name.ExplicitSchema && name.ExplicitCatalog && name.SchemaName == tree.PublicSchemaName &&
+		n.ExplicitSchema && !n.ExplicitCatalog && n.SchemaName == name.CatalogName {
+		name.SchemaName, name.ExplicitSchema = "", false
+	}
 	var schemaClause string
-	if n.ExplicitSchema {
+	if name.ExplicitSchema {
 		schema := lex.EscapeSQLString(name.Schema())
 		if name.Schema() == sessiondata.PgTempSchemaName {
 			schema = lex.EscapeSQLString(d.evalCtx.SessionData.SearchPath.GetTemporarySchemaName())
diff --git a/pkg/sql/logictest/testdata/logic_test/schema b/pkg/sql/logictest/testdata/logic_test/schema
index 223d94562906..f7860d9f1af9 100644
--- a/pkg/sql/logictest/testdata/logic_test/schema
+++ b/pkg/sql/logictest/testdata/logic_test/schema
@@ -569,3 +569,45 @@ SELECT privilege_type FROM [SHOW GRANTS ON schema s FOR testuser]
 ----
 CREATE
 USAGE
+
+subtest show_tables
+
+statement ok
+CREATE DATABASE for_show;
+
+statement ok;
+USE for_show;
+
+statement ok;
+CREATE TABLE t1 (i INT PRIMARY KEY);
+
+statement ok;
+CREATE SCHEMA sc1;
+
+statement ok;
+CREATE TABLE sc1.t1 (i INT PRIMARY KEY);
+
+query TT
+SELECT schema_name, table_name FROM [SHOW TABLES]
+----
+public t1
+sc1    t1
+
+query TT
+SELECT schema_name, table_name FROM [SHOW TABLES FROM sc1]
+----
+sc1    t1
+
+statement ok
+USE test
+
+query TT
+SELECT schema_name, table_name FROM [SHOW TABLES FROM for_show]
+----
+public t1
+sc1    t1
+
+query TT
+SELECT schema_name, table_name FROM [SHOW TABLES FROM for_show.sc1]
+----
+sc1    t1