feat(compiler): Support LEFT JOIN on aliased table (#2873)

Author: kyleconroy

internal/compiler/output_columns.go

@@ -403,7 +403,8 @@ func (c *Compiler) outputColumns(qc *QueryCatalog, node ast.Node) ([]*Column, er
 				continue
 			}
 			for _, f := range n.FromClause.Items {
-				if res := isTableRequired(f, col, tableRequired); res != tableNotFound {
+				res := isTableRequired(f, col, tableRequired)
+				if res != tableNotFound {
 					col.NotNull = res == tableRequired
 					break
 				}
@@ -423,10 +424,12 @@ const (
 func isTableRequired(n ast.Node, col *Column, prior int) int {
 	switch n := n.(type) {
 	case *ast.RangeVar:
-		if n.Alias == nil && *n.Relname == col.Table.Name {
-			return prior
+		tableMatch := *n.Relname == col.Table.Name
+		aliasMatch := true
+		if n.Alias != nil && col.TableAlias != "" {
+			aliasMatch = *n.Alias.Aliasname == col.TableAlias
 		}
-		if n.Alias != nil && *n.Alias.Aliasname == col.TableAlias && *n.Relname == col.Table.Name {
+		if aliasMatch && tableMatch {
 			return prior
 		}
 	case *ast.JoinExpr:
@@ -673,13 +676,13 @@ func outputColumnRefs(res *ast.ResTarget, tables []*Table, node *ast.ColumnRef)
 			continue
 		}
 		for _, c := range t.Columns {
+
 			if c.Name == name {
 				found += 1
 				cname := c.Name
 				if res.Name != nil {
 					cname = *res.Name
 				}
-
 				cols = append(cols, &Column{
 					Name:         cname,
 					Type:         c.Type,

internal/endtoend/testdata/join_left_table_alias/issue.md

@@ -0,0 +1 @@
+https://github.com/sqlc-dev/sqlc/issues/1897

internal/endtoend/testdata/join_left_table_alias/postgresql/pgx/go/db.go

@@ -0,0 +1,9 @@
+-- name: JoinBar :one
+SELECT f.id, info
+FROM foo f
+LEFT JOIN bar b ON b.foo_id = f.id;
+
+-- name: JoinBarAlias :one
+SELECT f.id, b.info
+FROM foo f
+LEFT JOIN bar b ON b.foo_id = f.id;

internal/endtoend/testdata/join_left_table_alias/postgresql/pgx/go/models.go

@@ -0,0 +1,9 @@
+CREATE TABLE foo (
+	id BIGINT PRIMARY KEY
+);
+
+CREATE TABLE bar
+(
+    foo_id  BIGINT NOT NULL,
+    info    TEXT NOT NULL
+);

internal/endtoend/testdata/join_left_table_alias/postgresql/pgx/go/query.sql.go

@@ -0,0 +1,10 @@
+version: "2"
+sql:
+  - engine: "postgresql"
+    schema: "schema.sql"
+    queries: "query.sql"
+    gen:
+      go:
+        package: "querytest"
+        out: "go"
+        sql_package: "pgx/v5"