Merge branch 'angela/union' of https://github.com/dolthub/go-mysql-server into angela/union

Author: angelamayxie

sql/planbuilder/set_op.go

@@ -16,7 +16,6 @@ package planbuilder
 
 import (
 	"fmt"
-	"github.com/dolthub/go-mysql-server/sql/types"
 	"reflect"
 
 	ast "github.com/dolthub/vitess/go/vt/sqlparser"
@@ -25,6 +24,7 @@ import (
 	"github.com/dolthub/go-mysql-server/sql/expression"
 	"github.com/dolthub/go-mysql-server/sql/plan"
 	"github.com/dolthub/go-mysql-server/sql/transform"
+	"github.com/dolthub/go-mysql-server/sql/types"
 )
 
 func hasRecursiveCte(node sql.Node) bool {