From 045b4d6d2aec55681bfea250c69287884f36a5e8 Mon Sep 17 00:00:00 2001
From: Constantin Schomburg <me@cschomburg.com>
Date: Sun, 4 Jan 2015 13:47:25 +0100
Subject: [PATCH] Fix error when chaining empty where conditions

---
 query_test.go    | 19 +++++++++++++++++++
 scope_private.go | 12 +++++++++---
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/query_test.go b/query_test.go
index a7e3c325..be309ed7 100644
--- a/query_test.go
+++ b/query_test.go
@@ -229,6 +229,25 @@ func TestSearchWithMap(t *testing.T) {
 	}
 }
 
+func TestSearchWithEmptyChain(t *testing.T) {
+	user1 := User{Name: "ChainSearchUser1", Age: 1, Birthday: now.MustParse("2000-1-1")}
+	user2 := User{Name: "ChainearchUser2", Age: 10, Birthday: now.MustParse("2010-1-1")}
+	user3 := User{Name: "ChainearchUser3", Age: 20, Birthday: now.MustParse("2020-1-1")}
+	DB.Save(&user1).Save(&user2).Save(&user3)
+
+	if DB.Where("").Where("").First(&User{}).Error != nil {
+		t.Errorf("Should not raise any error if searching with empty strings")
+	}
+
+	if DB.Where(&User{}).Where("name = ?", user1.Name).First(&User{}).Error != nil {
+		t.Errorf("Should not raise any error if searching with empty struct")
+	}
+
+	if DB.Where(map[string]interface{}{}).Where("name = ?", user1.Name).First(&User{}).Error != nil {
+		t.Errorf("Should not raise any error if searching with empty map")
+	}
+}
+
 func TestSelect(t *testing.T) {
 	user1 := User{Name: "SelectUser1"}
 	DB.Save(&user1)
diff --git a/scope_private.go b/scope_private.go
index c2a1428e..a109b5ae 100644
--- a/scope_private.go
+++ b/scope_private.go
@@ -176,15 +176,21 @@ func (scope *Scope) whereSql() (sql string) {
 	}
 
 	for _, clause := range scope.Search.WhereConditions {
-		andConditions = append(andConditions, scope.buildWhereCondition(clause))
+		if sql := scope.buildWhereCondition(clause); sql != "" {
+			andConditions = append(andConditions, sql)
+		}
 	}
 
 	for _, clause := range scope.Search.OrConditions {
-		orConditions = append(orConditions, scope.buildWhereCondition(clause))
+		if sql := scope.buildWhereCondition(clause); sql != "" {
+			orConditions = append(orConditions, sql)
+		}
 	}
 
 	for _, clause := range scope.Search.NotConditions {
-		andConditions = append(andConditions, scope.buildNotCondition(clause))
+		if sql := scope.buildNotCondition(clause); sql != "" {
+			andConditions = append(andConditions, sql)
+		}
 	}
 
 	orSql := strings.Join(orConditions, " OR ")