refs #164: new API SelectMore to add more cols to SELECT after callin…

…g Select()

select.go

@@ -134,6 +134,13 @@ func (sb *SelectBuilder) Select(col ...string) *SelectBuilder {
 	return sb
 }
 
+// SelectMore adds more columns in SELECT.
+func (sb *SelectBuilder) SelectMore(col ...string) *SelectBuilder {
+	sb.selectCols = append(sb.selectCols, col...)
+	sb.marker = selectMarkerAfterSelect
+	return sb
+}
+
 // Distinct marks this SELECT as DISTINCT.
 func (sb *SelectBuilder) Distinct() *SelectBuilder {
 	sb.distinct = true

select_test.go

@@ -6,6 +6,9 @@ package sqlbuilder
 import (
 	"database/sql"
 	"fmt"
+	"testing"
+
+	"github.com/huandu/go-assert"
 )
 
 func ExampleSelect() {
@@ -364,3 +367,11 @@ func ExampleSelectBuilder_With() {
 	// Output:
 	// WITH users AS (SELECT id, name FROM users WHERE prime IS NOT NULL), orders AS (SELECT id, user_id FROM orders) SELECT orders.id FROM orders JOIN users ON orders.user_id = users.id LIMIT 10
 }
+
+func TestSelectBuilderSelectMore(t *testing.T) {
+	a := assert.New(t)
+	sb := Select("id").SQL("/* first */").Where(
+		"name IS NOT NULL",
+	).SQL("/* second */").SelectMore("name").SQL("/* third */")
+	a.Equal(sb.String(), "SELECT id, name /* first */ /* third */ WHERE name IS NOT NULL /* second */")
+}