From e472f58c1f4c55755926965d1476cfae6439a4f4 Mon Sep 17 00:00:00 2001
From: sivagollapalli <sivagollapalli88@gmail.com>
Date: Wed, 5 Dec 2018 15:44:14 +0530
Subject: [PATCH] [#82] Added FROM clause to update builder

---
 update.go      | 7 +++++++
 update_test.go | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/update.go b/update.go
index 682906bc..240acca1 100644
--- a/update.go
+++ b/update.go
@@ -21,6 +21,7 @@ type updateData struct {
 	Limit             string
 	Offset            string
 	Suffixes          exprs
+	From              Sqlizer
 }
 
 type setClause struct {
@@ -230,3 +231,9 @@ func (b UpdateBuilder) Offset(offset uint64) UpdateBuilder {
 func (b UpdateBuilder) Suffix(sql string, args ...interface{}) UpdateBuilder {
 	return builder.Append(b, "Suffixes", Expr(sql, args...)).(UpdateBuilder)
 }
+
+// From adds FROM clause to the query
+// FROM is valid construct in postgresql only.
+func (b UpdateBuilder) From(from string) UpdateBuilder {
+	return builder.Set(b, "From", newPart(from)).(UpdateBuilder)
+}
diff --git a/update_test.go b/update_test.go
index 13795c3d..54b533ad 100644
--- a/update_test.go
+++ b/update_test.go
@@ -66,3 +66,9 @@ func TestUpdateBuilderNoRunner(t *testing.T) {
 	_, err := b.Exec()
 	assert.Equal(t, RunnerNotSet, err)
 }
+
+func TestUpdateBuilderFromClause(t *testing.T) {
+	sql, _, err := Update("employees").Set("sales_count", 100).From("accounts").Where("accounts.name = ?", "ACME").ToSql()
+	assert.NoError(t, err)
+	assert.Equal(t, "UPDATE employees SET sales_count = ? WHERE accounts.name = ?", sql)
+}