From 0e97acd3789c6f6509fa488005f2aaa2f8d910ff Mon Sep 17 00:00:00 2001
From: Andres Taylor <andres@planetscale.com>
Date: Tue, 28 May 2024 14:19:17 +0200
Subject: [PATCH] fix: remove keyspace when merging subqueries

Signed-off-by: Andres Taylor <andres@planetscale.com>
---
 .../operators/subquery_planning.go            |  1 +
 .../planbuilder/testdata/filter_cases.json    | 23 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/go/vt/vtgate/planbuilder/operators/subquery_planning.go b/go/vt/vtgate/planbuilder/operators/subquery_planning.go
index 30d5119ca98..145a0707347 100644
--- a/go/vt/vtgate/planbuilder/operators/subquery_planning.go
+++ b/go/vt/vtgate/planbuilder/operators/subquery_planning.go
@@ -467,6 +467,7 @@ func tryMergeSubqueryWithOuter(ctx *plancontext.PlanningContext, subQuery *SubQu
 		return outer, NoRewrite
 	}
 	exprs := subQuery.GetMergePredicates()
+	sqlparser.RemoveKeyspace(subQuery.Original)
 	merger := &subqueryRouteMerger{
 		outer:    outer,
 		original: subQuery.Original,
diff --git a/go/vt/vtgate/planbuilder/testdata/filter_cases.json b/go/vt/vtgate/planbuilder/testdata/filter_cases.json
index 7c44c5f5cf1..6eae5c603b3 100644
--- a/go/vt/vtgate/planbuilder/testdata/filter_cases.json
+++ b/go/vt/vtgate/planbuilder/testdata/filter_cases.json
@@ -870,6 +870,29 @@
       ]
     }
   },
+  {
+    "comment": "Merging subqueries should remove keyspace from query",
+    "query": "select u.id from user.user as u where not exists (select 1 from user.user_extra as ue where u.id = ue.user_id)",
+    "plan": {
+      "QueryType": "SELECT",
+      "Original": "select u.id from user.user as u where not exists (select 1 from user.user_extra as ue where u.id = ue.user_id)",
+      "Instructions": {
+        "OperatorType": "Route",
+        "Variant": "Scatter",
+        "Keyspace": {
+          "Name": "user",
+          "Sharded": true
+        },
+        "FieldQuery": "select u.id from `user` as u where 1 != 1",
+        "Query": "select u.id from `user` as u where not exists (select 1 from user_extra as ue where u.id = ue.user_id)",
+        "Table": "`user`"
+      },
+      "TablesUsed": [
+        "user.user",
+        "user.user_extra"
+      ]
+    }
+  },
   {
     "comment": "Single table equality route with unsigned value",
     "query": "select id from user where name = 18446744073709551615",