From 5521b1eec9d8b6496a964862d6a47debd1a175b2 Mon Sep 17 00:00:00 2001
From: Saif Alharthi <saif@saifalharthi.me>
Date: Thu, 12 Dec 2019 12:26:05 -0800
Subject: [PATCH] Add fix for SHOW FULL COLUMNS

Signed-off-by: Saif Alharthi <saif@saifalharthi.me>

Add test for query with qualifer

Signed-off-by: Saif Alharthi <saif@saifalharthi.me>
---
 go.mod                        | 4 ++--
 go/vt/vtgate/executor.go      | 8 ++++++++
 go/vt/vtgate/executor_test.go | 7 +++++++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/go.mod b/go.mod
index 44d8c461dd1..af52af73134 100644
--- a/go.mod
+++ b/go.mod
@@ -17,7 +17,7 @@ require (
 	github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f // indirect
 	github.com/dchest/safefile v0.0.0-20151022103144-855e8d98f185 // indirect
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible // indirect
-	github.com/evanphx/json-patch v4.5.0+incompatible // indirect
+	github.com/evanphx/json-patch v4.5.0+incompatible
 	github.com/ghodss/yaml v0.0.0-20161207003320-04f313413ffd // indirect
 	github.com/go-ini/ini v1.12.0 // indirect
 	github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b
@@ -45,7 +45,7 @@ require (
 	github.com/klauspost/crc32 v1.2.0 // indirect
 	github.com/klauspost/pgzip v1.2.0
 	github.com/kr/pretty v0.1.0 // indirect
-	github.com/krishicks/yaml-patch v0.0.10 // indirect
+	github.com/krishicks/yaml-patch v0.0.10
 	github.com/mattn/go-runewidth v0.0.1 // indirect
 	github.com/minio/minio-go v0.0.0-20190131015406-c8a261de75c1
 	github.com/mitchellh/go-testing-interface v1.0.0 // indirect
diff --git a/go/vt/vtgate/executor.go b/go/vt/vtgate/executor.go
index b3c9e2c8980..5499160dab1 100644
--- a/go/vt/vtgate/executor.go
+++ b/go/vt/vtgate/executor.go
@@ -840,6 +840,14 @@ func (e *Executor) handleShow(ctx context.Context, safeSession *SafeSession, sql
 				}
 			}
 		}
+	case sqlparser.KeywordString(sqlparser.COLUMNS):
+		if !show.OnTable.Qualifier.IsEmpty() {
+			destKeyspace = show.OnTable.Qualifier.String()
+			show.OnTable.Qualifier = sqlparser.NewTableIdent("")
+		} else {
+			break
+		}
+		sql = sqlparser.String(show)
 	case sqlparser.KeywordString(sqlparser.TABLES):
 		if show.ShowTablesOpt != nil && show.ShowTablesOpt.DbName != "" {
 			if destKeyspace == "" {
diff --git a/go/vt/vtgate/executor_test.go b/go/vt/vtgate/executor_test.go
index 8767cd0928c..8a42e884bc6 100644
--- a/go/vt/vtgate/executor_test.go
+++ b/go/vt/vtgate/executor_test.go
@@ -890,6 +890,13 @@ func TestExecutorShow(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
+
+	// Test SHOW FULL COLUMNS FROM where query has a qualifier
+	_, err = executor.Execute(context.Background(), "TestExecute", session, fmt.Sprintf("show full columns from %v.table1", KsTestUnsharded), nil)
+	if err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+
 	// Just test for first & last.
 	qr.Rows = [][]sqltypes.Value{qr.Rows[0], qr.Rows[len(qr.Rows)-1]}
 	wantqr = &sqltypes.Result{