sql/parse: generate sort before project.

* Sort was being generated after Project,
  so it was not possible to ORDER BY
  by a field not included in SELECT.

Author: smola

sql/parse/parse.go

@@ -282,11 +282,12 @@ func (p *parser) buildPlan() (sql.Node, error) {
 		node = plan.NewFilter(p.filterClauses[0], node)
 	}
 
-	node = plan.NewProject(p.projection, node)
 	if len(p.sortFields) > 0 {
 		node = plan.NewSort(p.sortFields, node)
 	}
 
+	node = plan.NewProject(p.projection, node)
+
 	if p.limit != nil {
 		node = plan.NewLimit(int64(*p.limit), node)
 	}

sql/parse/parse_test.go

@@ -54,13 +54,13 @@ var fixtures = map[string]sql.Node{
 			plan.NewUnresolvedRelation("foo"),
 		),
 	),
-	`SELECT foo, bar FROM foo ORDER BY baz DESC;`: plan.NewSort(
-		[]plan.SortField{{expression.NewUnresolvedColumn("baz"), plan.Descending}},
-		plan.NewProject(
-			[]sql.Expression{
-				expression.NewUnresolvedColumn("foo"),
-				expression.NewUnresolvedColumn("bar"),
-			},
+	`SELECT foo, bar FROM foo ORDER BY baz DESC;`: plan.NewProject(
+		[]sql.Expression{
+			expression.NewUnresolvedColumn("foo"),
+			expression.NewUnresolvedColumn("bar"),
+		},
+		plan.NewSort(
+			[]plan.SortField{{expression.NewUnresolvedColumn("baz"), plan.Descending}},
 			plan.NewUnresolvedRelation("foo"),
 		),
 	),
@@ -80,25 +80,25 @@ var fixtures = map[string]sql.Node{
 		),
 	),
 	`SELECT foo, bar FROM foo ORDER BY baz DESC LIMIT 1;`: plan.NewLimit(int64(1),
-		plan.NewSort(
-			[]plan.SortField{{expression.NewUnresolvedColumn("baz"), plan.Descending}},
-			plan.NewProject(
-				[]sql.Expression{
-					expression.NewUnresolvedColumn("foo"),
-					expression.NewUnresolvedColumn("bar"),
-				},
+		plan.NewProject(
+			[]sql.Expression{
+				expression.NewUnresolvedColumn("foo"),
+				expression.NewUnresolvedColumn("bar"),
+			},
+			plan.NewSort(
+				[]plan.SortField{{expression.NewUnresolvedColumn("baz"), plan.Descending}},
 				plan.NewUnresolvedRelation("foo"),
 			),
 		),
 	),
 	`SELECT foo, bar FROM foo WHERE qux = 1 ORDER BY baz DESC LIMIT 1;`: plan.NewLimit(int64(1),
-		plan.NewSort(
-			[]plan.SortField{{expression.NewUnresolvedColumn("baz"), plan.Descending}},
-			plan.NewProject(
-				[]sql.Expression{
-					expression.NewUnresolvedColumn("foo"),
-					expression.NewUnresolvedColumn("bar"),
-				},
+		plan.NewProject(
+			[]sql.Expression{
+				expression.NewUnresolvedColumn("foo"),
+				expression.NewUnresolvedColumn("bar"),
+			},
+			plan.NewSort(
+				[]plan.SortField{{expression.NewUnresolvedColumn("baz"), plan.Descending}},
 				plan.NewFilter(
 					expression.NewEquals(
 						expression.NewUnresolvedColumn("qux"),