[release-17.0] Make column resolution closer to MySQL (#14426) (#14429)

Signed-off-by: Andres Taylor <[email protected]>
Co-authored-by: Andres Taylor <[email protected]>

go/vt/vtgate/planbuilder/operators/queryprojection.go

@@ -460,29 +460,47 @@ func (qp *QueryProjection) isExprInGroupByExprs(ctx *plancontext.PlanningContext
 }
 
 // GetSimplifiedExpr takes an expression used in ORDER BY or GROUP BY, and returns an expression that is simpler to evaluate
-func (qp *QueryProjection) GetSimplifiedExpr(e sqlparser.Expr) sqlparser.Expr {
+func (qp *QueryProjection) GetSimplifiedExpr(e sqlparser.Expr) (found sqlparser.Expr) {
+	if qp == nil {
+		return e
+	}
 	// If the ORDER BY is against a column alias, we need to remember the expression
 	// behind the alias. The weightstring(.) calls needs to be done against that expression and not the alias.
 	// Eg - select music.foo as bar, weightstring(music.foo) from music order by bar
 
-	colExpr, isColName := e.(*sqlparser.ColName)
-	if !(isColName && colExpr.Qualifier.IsEmpty()) {
-		// we are only interested in unqualified column names. if it's not a column name and not
+	in, isColName := e.(*sqlparser.ColName)
+	if !(isColName && in.Qualifier.IsEmpty()) {
+		// we are only interested in unqualified column names. if it's not a column name and not unqualified, we're done
 		return e
 	}
 
 	for _, selectExpr := range qp.SelectExprs {
-		aliasedExpr, isAliasedExpr := selectExpr.Col.(*sqlparser.AliasedExpr)
-		if !isAliasedExpr {
+		ae, ok := selectExpr.Col.(*sqlparser.AliasedExpr)
+		if !ok {
 			continue
 		}
-		aliased := !aliasedExpr.As.IsEmpty()
-		if aliased && colExpr.Name.Equal(aliasedExpr.As) {
-			return aliasedExpr.Expr
+		aliased := !ae.As.IsEmpty()
+		if aliased {
+			if in.Name.Equal(ae.As) {
+				return ae.Expr
+			}
+		} else {
+			seCol, ok := ae.Expr.(*sqlparser.ColName)
+			if !ok {
+				continue
+			}
+			if seCol.Name.Equal(in.Name) {
+				// If the column name matches, we have a match, even if the table name is not listed
+				return ae.Expr
+			}
 		}
 	}
 
-	return e
+	if found == nil {
+		found = e
+	}
+
+	return found
 }
 
 // toString should only be used for tests

go/vt/vtgate/planbuilder/testdata/aggr_cases.json

@@ -4592,7 +4592,7 @@
       "Instructions": {
         "OperatorType": "Sort",
         "Variant": "Memory",
-        "OrderBy": "(1|3) ASC",
+        "OrderBy": "(0|3) ASC",
         "ResultColumns": 3,
         "Inputs": [
           {
@@ -4607,8 +4607,8 @@
                   "Name": "user",
                   "Sharded": true
                 },
-                "FieldQuery": "select id, b as id, count(*), weight_string(b) from `user` where 1 != 1",
-                "Query": "select id, b as id, count(*), weight_string(b) from `user`",
+                "FieldQuery": "select id, b as id, count(*), weight_string(id) from `user` where 1 != 1",
+                "Query": "select id, b as id, count(*), weight_string(id) from `user`",
                 "Table": "`user`"
               }
             ]
@@ -4697,9 +4697,9 @@
                   "Name": "user",
                   "Sharded": true
                 },
-                "FieldQuery": "select `user`.id, weight_string(id) from `user` where 1 != 1 group by id, weight_string(id)",
+                "FieldQuery": "select `user`.id, weight_string(`user`.id) from `user` where 1 != 1 group by id, weight_string(`user`.id)",
                 "OrderBy": "(0|1) ASC",
-                "Query": "select `user`.id, weight_string(id) from `user` group by id, weight_string(id) order by id asc",
+                "Query": "select `user`.id, weight_string(`user`.id) from `user` group by id, weight_string(`user`.id) order by id asc",
                 "Table": "`user`"
               },
               {

go/vt/vtgate/planbuilder/testdata/select_cases.json

@@ -8411,5 +8411,84 @@
         "user.customer"
       ]
     }
+  },
+  {
+    "comment": "column with qualifier is correctly used",
+    "query": "select u.foo, ue.foo as apa from user u, user_extra ue order by foo ",
+    "v3-plan": {
+      "QueryType": "SELECT",
+      "Original": "select u.foo, ue.foo as apa from user u, user_extra ue order by foo ",
+      "Instructions": {
+        "OperatorType": "Join",
+        "Variant": "Join",
+        "JoinColumnIndexes": "L:0,R:0",
+        "TableName": "`user`_user_extra",
+        "Inputs": [
+          {
+            "OperatorType": "Route",
+            "Variant": "Scatter",
+            "Keyspace": {
+              "Name": "user",
+              "Sharded": true
+            },
+            "FieldQuery": "select u.foo, weight_string(u.foo) from `user` as u where 1 != 1",
+            "OrderBy": "(0|1) ASC",
+            "Query": "select u.foo, weight_string(u.foo) from `user` as u order by foo asc",
+            "ResultColumns": 1,
+            "Table": "`user`"
+          },
+          {
+            "OperatorType": "Route",
+            "Variant": "Scatter",
+            "Keyspace": {
+              "Name": "user",
+              "Sharded": true
+            },
+            "FieldQuery": "select ue.foo as apa from user_extra as ue where 1 != 1",
+            "Query": "select ue.foo as apa from user_extra as ue",
+            "Table": "user_extra"
+          }
+        ]
+      }
+    },
+    "gen4-plan": {
+      "QueryType": "SELECT",
+      "Original": "select u.foo, ue.foo as apa from user u, user_extra ue order by foo ",
+      "Instructions": {
+        "OperatorType": "Join",
+        "Variant": "Join",
+        "JoinColumnIndexes": "L:0,R:0",
+        "TableName": "`user`_user_extra",
+        "Inputs": [
+          {
+            "OperatorType": "Route",
+            "Variant": "Scatter",
+            "Keyspace": {
+              "Name": "user",
+              "Sharded": true
+            },
+            "FieldQuery": "select u.foo, weight_string(u.foo) from `user` as u where 1 != 1",
+            "OrderBy": "(0|1) ASC",
+            "Query": "select u.foo, weight_string(u.foo) from `user` as u order by foo asc",
+            "Table": "`user`"
+          },
+          {
+            "OperatorType": "Route",
+            "Variant": "Scatter",
+            "Keyspace": {
+              "Name": "user",
+              "Sharded": true
+            },
+            "FieldQuery": "select ue.foo as apa from user_extra as ue where 1 != 1",
+            "Query": "select ue.foo as apa from user_extra as ue",
+            "Table": "user_extra"
+          }
+        ]
+      },
+      "TablesUsed": [
+        "user.user",
+        "user.user_extra"
+      ]
+    }
   }
 ]