make a dummy execution if update without assignments

update.go

@@ -2,7 +2,6 @@ package sqlingo
 
 import (
 	"database/sql"
-	"errors"
 	"strconv"
 	"strings"
 )
@@ -79,15 +78,15 @@ func (s updateStatus) Limit(limit int) updateWithLimit {
 }
 
 func (s updateStatus) GetSQL() (string, error) {
+	if len(s.assignments) == 0 {
+		return "/* UPDATE without SET clause */ DO 0", nil
+	}
 	var sb strings.Builder
 	sb.Grow(128)
 
 	sb.WriteString("UPDATE ")
 	sb.WriteString(s.scope.Tables[0].GetSQL(s.scope))
 
-	if len(s.assignments) == 0 {
-		return "", errors.New("no set in update")
-	}
 	assignmentsSql, err := commaAssignments(s.scope, s.assignments)
 	if err != nil {
 		return "", err

update_test.go

@@ -26,16 +26,14 @@ func TestUpdate(t *testing.T) {
 		Execute()
 	assertLastSql(t, "UPDATE `table1` SET `field1` = 10 WHERE 1")
 
-	if _, err := db.Update(Table1).
+	_, _ = db.Update(Table1).
 		SetIf(false, field1, 10).
 		Where(trueExpression()).
-		Execute(); err == nil {
-		t.Error("should get error here")
-	}
+		Execute()
+	assertLastSql(t, "/* UPDATE without SET clause */ DO 0")
 
-	if _, err := db.Update(Table1).Limit(3).Execute(); err == nil {
-		t.Error("should get error here")
-	}
+	_, _ = db.Update(Table1).Limit(3).Execute()
+	assertLastSql(t, "/* UPDATE without SET clause */ DO 0")
 
 	errExp := &expression{
 		builder: func(scope scope) (string, error) {

utils_test.go

@@ -16,6 +16,7 @@ func assertLastSql(t *testing.T, expectedSql string) {
 	if sharedMockConn.lastSql != expectedSql {
 		t.Errorf("last sql [%s] expected [%s]", sharedMockConn.lastSql, expectedSql)
 	}
+	sharedMockConn.lastSql = ""
 }
 
 func assertError(t *testing.T, value interface{}) {