Added OrderPrepend #61

HISTORY.md

@@ -1,7 +1,8 @@
-## v7.1.1
+## v7.2.0
 
 * [FIXED] Sqlite3 does not accept SELECT * UNION (SELECT *) [#79](https://github.com/doug-martin/goqu/issues/79)
 * [FIXED] Where(Ex{}) causes panics [mysql] [#49](https://github.com/doug-martin/goqu/issues/49)
+* [ADDED] Support for OrderPrepend [#61](https://github.com/doug-martin/goqu/issues/49)
 
 ## v7.1.0
 

dataset.go

@@ -363,6 +363,12 @@ func (d *Dataset) OrderAppend(order ...exp.OrderedExpression) *Dataset {
 	return d.copy(d.clauses.OrderAppend(order...))
 }
 
+// Adds a more columns to the beginning of the current ORDER BY clause. If no order has be previously specified it is the same as
+// calling Order. See examples.
+func (d *Dataset) OrderPrepend(order ...exp.OrderedExpression) *Dataset {
+	return d.copy(d.clauses.OrderPrepend(order...))
+}
+
 // Removes the ORDER BY clause. See examples.
 func (d *Dataset) ClearOrder() *Dataset {
 	return d.copy(d.clauses.ClearOrder())

dataset_sql_example_test.go

@@ -271,6 +271,14 @@ func ExampleDataset_OrderAppend() {
 	// SELECT * FROM "test" ORDER BY "a" ASC, "b" DESC NULLS LAST
 }
 
+func ExampleDataset_OrderPrepend() {
+	ds := goqu.From("test").Order(goqu.C("a").Asc())
+	sql, _, _ := ds.OrderPrepend(goqu.C("b").Desc().NullsLast()).ToSQL()
+	fmt.Println(sql)
+	// Output:
+	// SELECT * FROM "test" ORDER BY "b" DESC NULLS LAST, "a" ASC
+}
+
 func ExampleDataset_ClearOrder() {
 	ds := goqu.From("test").Order(goqu.C("a").Asc())
 	sql, _, _ := ds.ClearOrder().ToSQL()

exp/clauses.go

@@ -37,6 +37,7 @@ type (
 		ClearOrder() Clauses
 		SetOrder(oes ...OrderedExpression) Clauses
 		OrderAppend(...OrderedExpression) Clauses
+		OrderPrepend(...OrderedExpression) Clauses
 
 		GroupBy() ColumnListExpression
 		SetGroupBy(cl ColumnListExpression) Clauses
@@ -285,6 +286,15 @@ func (c *clauses) OrderAppend(oes ...OrderedExpression) Clauses {
 	return ret
 }
 
+func (c *clauses) OrderPrepend(oes ...OrderedExpression) Clauses {
+	if c.order == nil {
+		return c.SetOrder(oes...)
+	}
+	ret := c.clone()
+	ret.order = NewOrderedColumnList(oes...).Append(ret.order.Columns()...)
+	return ret
+}
+
 func (c *clauses) GroupBy() ColumnListExpression {
 	return c.groupBy
 }

exp/clauses_test.go

@@ -344,6 +344,19 @@ func (ct *clausesTest) TestOrderAppend() {
 	assert.Equal(t, NewColumnListExpression(oe, oe2), c2.Order())
 }
 
+func (ct *clausesTest) TestOrderPrepend() {
+	t := ct.T()
+	oe := NewIdentifierExpression("", "", "a").Desc()
+	oe2 := NewIdentifierExpression("", "", "b").Desc()
+
+	c := NewClauses().SetOrder(oe)
+	c2 := c.OrderPrepend(oe2)
+
+	assert.Equal(t, NewColumnListExpression(oe), c.Order())
+
+	assert.Equal(t, NewColumnListExpression(oe2, oe), c2.Order())
+}
+
 func (ct *clausesTest) TestGroupBy() {
 	t := ct.T()
 	g := NewColumnListExpression(NewIdentifierExpression("", "", "a"))