orm: add support for ordering (#5624)

vlib/orm/orm_test.v

@@ -197,6 +197,11 @@ fn test_orm_sqlite() {
 	}
 	assert z.len == 2
 	assert z[0].id == 3
+
+	oldest := sql db {
+		select from User order age desc limit 1
+	}
+	assert oldest.age == 34
 }
 
 fn test_orm_pg() {

vlib/v/ast/ast.v

@@ -846,6 +846,9 @@ pub:
 	has_where   bool
 	has_offset  bool
 	offset_expr Expr
+	has_order   bool
+	order_expr  Expr
+	has_desc    bool
 	is_array    bool
 	table_type  table.Type
 	pos         token.Position
@@ -934,6 +937,7 @@ pub fn (expr Expr) position() token.Position {
 		}
 		// ast.None { }
 		PrefixExpr {
+
 			return expr.pos
 		}
 		// ast.ParExpr { }

vlib/v/checker/checker.v

@@ -2808,6 +2808,9 @@ fn (mut c Checker) sql_expr(mut node ast.SqlExpr) table.Type {
 	if node.has_limit {
 		c.expr(node.limit_expr)
 	}
+	if node.has_order {
+		c.expr(node.order_expr)
+	}
 	c.expr(node.db_expr)
 	return node.typ
 }

vlib/v/gen/sql.v

@@ -133,7 +133,16 @@ fn (mut g Gen) sql_select_expr(node ast.SqlExpr) {
 	if node.has_where && node.where_expr is ast.InfixExpr {
 		g.expr_to_sql(node.where_expr)
 	}
+	if node.has_order {
+		g.write(' ORDER BY ')
+		g.sql_side = .left
+		g.expr_to_sql(node.order_expr)
+		if node.has_desc {
+			g.write(' DESC ')
+		}
+	} else {
 		g.write(' ORDER BY id ')
+	}
 	if node.has_limit {
 		g.write(' LIMIT ')
 		g.expr_to_sql(node.limit_expr)

vlib/v/parser/sql.v

@@ -42,6 +42,18 @@ fn (mut p Parser) sql_expr() ast.Expr {
 	mut limit_expr := ast.Expr{}
 	mut has_offset := false
 	mut offset_expr := ast.Expr{}
+	mut has_order := false
+	mut order_expr := ast.Expr{}
+	mut has_desc := false
+	if p.tok.kind == .name && p.tok.lit == 'order' {
+		p.check_name() // `order`
+		has_order = true
+		order_expr = p.expr(0)
+		if p.tok.kind == .name && p.tok.lit == 'desc' {
+			p.check_name() // `desc`
+			has_desc = true
+		}
+	}
 	if p.tok.kind == .name && p.tok.lit == 'limit' {
 		// `limit 1` means that a single object is returned
 		p.check_name() // `limit`
@@ -77,6 +89,9 @@ fn (mut p Parser) sql_expr() ast.Expr {
 		limit_expr: limit_expr
 		has_offset: has_offset
 		offset_expr: offset_expr
+		has_order: has_order
+		order_expr: order_expr
+		has_desc: has_desc
 		is_array: !query_one
 		pos: pos
 	}