From a1c01cde78894fa9395b7bc6084a11385c29df79 Mon Sep 17 00:00:00 2001
From: Manan Gupta <manan@planetscale.com>
Date: Fri, 13 Oct 2023 13:52:11 +0530
Subject: [PATCH] wip

---
 .../planbuilder/operators/query_planning.go   | 38 ++++++++++---------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/go/vt/vtgate/planbuilder/operators/query_planning.go b/go/vt/vtgate/planbuilder/operators/query_planning.go
index c06a10098ca..dfa35cf7c49 100644
--- a/go/vt/vtgate/planbuilder/operators/query_planning.go
+++ b/go/vt/vtgate/planbuilder/operators/query_planning.go
@@ -22,6 +22,7 @@ import (
 	"math/rand"
 	"time"
 	"unsafe"
+
 	"vitess.io/vitess/go/test/dbg"
 	"vitess.io/vitess/go/vt/sqlparser"
 	"vitess.io/vitess/go/vt/vtgate/planbuilder/operators/ops"
@@ -427,21 +428,21 @@ func exposeColumnsThroughDerivedTable(ctx *plancontext.PlanningContext, p *Proje
 				return
 			}
 
+			// If we didn't find it, and we are dealing with a ColName, we have to add it to the derived table
+			colExpr, ok := this.(*sqlparser.ColName)
+			if !ok {
+				return
+			}
+
 			// First we check if this expression is already being returned
 			for _, column := range cols {
-				if ctx.SemTable.EqualsExprWithDeps(column.Expr, this) {
-					col := sqlparser.NewColName(column.As.String())
+				if ctx.SemTable.EqualsExprWithDeps(column.Expr, colExpr) {
+					col := sqlparser.NewColName(column.ColumnName())
 					cursor.Replace(col)
 					return
 				}
 			}
 
-			// If we didn't find it, and we are dealing with a ColName, we have to add it to the derived table
-			colExpr, ok := this.(*sqlparser.ColName)
-			if !ok {
-				return
-			}
-
 			colAlias := fmt.Sprintf("%s_vt_%s_%s", p.DT.Alias, sqlparser.String(colExpr), RandString(2))
 
 			newCol := sqlparser.NewColName(colAlias)
@@ -463,20 +464,21 @@ func exposeColumnsThroughDerivedTable(ctx *plancontext.PlanningContext, p *Proje
 		return e, nil
 	}
 
-	for i, pred := range src.JoinPredicates {
-		x, err := pred.Map(f)
+	//for i, pred := range src.JoinPredicates {
+	//	x, err := pred.Map(f)
+	//	if err != nil {
+	//		return err
+	//	}
+	//	src.JoinPredicates[i] = x
+	//}
+
+	for i, col := range src.JoinColumns {
+		var err error
+		src.JoinColumns[i], err = col.Map(f)
 		if err != nil {
 			return err
 		}
-		src.JoinPredicates[i] = x
 	}
-
-	// for i, col := range src.JoinColumns {
-	// 	src.JoinColumns[i], err = col.Map(f)
-	// 	if err != nil {
-	// 		return err
-	// 	}
-	// }
 	return nil
 }