diff --git a/conn_pool.go b/conn_pool.go
index ca4bd30..dd45cec 100644
--- a/conn_pool.go
+++ b/conn_pool.go
@@ -61,7 +61,7 @@ func (pool ConnPool) QueryContext(ctx context.Context, query string, args ...int
 		return nil, err
 	}
 
-	pool.sharding.querys.Store("last_query", query)
+	pool.sharding.querys.Store("last_query", stQuery)
 
 	if table != "" {
 		if r, ok := pool.sharding.Resolvers[table]; ok {
diff --git a/sharding_test.go b/sharding_test.go
index e7caa24..b5c6f9e 100644
--- a/sharding_test.go
+++ b/sharding_test.go
@@ -60,10 +60,10 @@ var (
 				default:
 					return "", err
 				}
-				return fmt.Sprintf("_%03d", userId%8), nil
+				return fmt.Sprintf("_%02d", userId%4), nil
 			},
 			ShardingAlgorithmByPrimaryKey: func(id int64) (suffix string) {
-				return fmt.Sprintf("_%03d", keygen.TableIdx(id))
+				return fmt.Sprintf("_%02d", keygen.TableIdx(id))
 			},
 			PrimaryKeyGenerate: func(tableIdx int64) int64 {
 				return keygen.Next(tableIdx)
@@ -72,77 +72,85 @@ var (
 	})
 )
 
-var tables = []string{"orders", "categories"}
-
 func init() {
 	dropTables()
 	err := db.AutoMigrate(&Order{}, &Category{})
 	if err != nil {
 		panic(err)
 	}
+	stables := []string{"orders_00", "orders_01", "orders_02", "orders_03"}
+	for _, table := range stables {
+		db.Exec(`CREATE TABLE ` + table + ` (
+			id BIGSERIAL PRIMARY KEY,
+			user_id bigint,
+			product text
+		)`)
+	}
+
 	db.Use(&sharding)
 }
 
 func dropTables() {
-	for _, tableName := range tables {
-		db.Exec("DROP TABLE IF EXISTS " + tableName)
+	tables := []string{"orders", "orders_00", "orders_01", "orders_02", "orders_03", "categories"}
+	for _, table := range tables {
+		db.Exec("DROP TABLE IF EXISTS " + table)
 	}
 }
 
 func TestInsert(t *testing.T) {
 	tx := db.Create(&Order{ID: 100, UserID: 100, Product: "iPhone"})
-	assertQueryResult(t, `INSERT INTO "orders_004" ("user_id", "product", "id") VALUES ($1, $2, $3) RETURNING "id"`, tx)
+	assertQueryResult(t, `INSERT INTO "orders_00" ("user_id", "product", "id") VALUES ($1, $2, $3) RETURNING "id"`, tx)
 }
 
 func TestFillID(t *testing.T) {
 	db.Create(&Order{UserID: 100, Product: "iPhone"})
 	lastQuery := sharding.LastQuery()
-	assert.Equal(t, `INSERT INTO "orders_004" ("user_id", "product", "id") VALUES`, lastQuery[0:57])
+	assert.Equal(t, `INSERT INTO "orders_00" ("user_id", "product", "id") VALUES`, lastQuery[0:59])
 }
 
 func TestSelect1(t *testing.T) {
-	tx := db.Model(&Order{}).Where("user_id", 101).Where("id", keygen.Next(24)).Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_024" WHERE "user_id" = $1 AND "id" = $2`, tx)
+	tx := db.Model(&Order{}).Where("user_id", 101).Where("id", keygen.Next(1)).Find(&[]Order{})
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "user_id" = $1 AND "id" = $2`, tx)
 }
 
 func TestSelect2(t *testing.T) {
-	tx := db.Model(&Order{}).Where("id", keygen.Next(24)).Where("user_id", 101).Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_005" WHERE "id" = $1 AND "user_id" = $2`, tx)
+	tx := db.Model(&Order{}).Where("id", keygen.Next(1)).Where("user_id", 101).Find(&[]Order{})
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "id" = $1 AND "user_id" = $2`, tx)
 }
 
 func TestSelect3(t *testing.T) {
-	tx := db.Model(&Order{}).Where("id", keygen.Next(24)).Where("user_id = 101").Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_005" WHERE "id" = $1 AND "user_id" = 101`, tx)
+	tx := db.Model(&Order{}).Where("id", keygen.Next(1)).Where("user_id = 101").Find(&[]Order{})
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "id" = $1 AND "user_id" = 101`, tx)
 }
 
 func TestSelect4(t *testing.T) {
 	tx := db.Model(&Order{}).Where("product", "iPad").Where("user_id", 100).Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_004" WHERE "product" = $1 AND "user_id" = $2`, tx)
+	assertQueryResult(t, `SELECT * FROM "orders_00" WHERE "product" = $1 AND "user_id" = $2`, tx)
 }
 
 func TestSelect5(t *testing.T) {
 	tx := db.Model(&Order{}).Where("user_id = 101").Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_005" WHERE "user_id" = 101`, tx)
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "user_id" = 101`, tx)
 }
 
 func TestSelect6(t *testing.T) {
-	tx := db.Model(&Order{}).Where("id", keygen.Next(24)).Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_024" WHERE "id" = $1`, tx)
+	tx := db.Model(&Order{}).Where("id", keygen.Next(2)).Find(&[]Order{})
+	assertQueryResult(t, `SELECT * FROM "orders_02" WHERE "id" = $1`, tx)
 }
 
 func TestSelect7(t *testing.T) {
-	tx := db.Model(&Order{}).Where("user_id", 101).Where("id > ?", keygen.Next(24)).Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_005" WHERE "user_id" = $1 AND "id" > $2`, tx)
+	tx := db.Model(&Order{}).Where("user_id", 101).Where("id > ?", keygen.Next(1)).Find(&[]Order{})
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "user_id" = $1 AND "id" > $2`, tx)
 }
 
 func TestSelect8(t *testing.T) {
-	tx := db.Model(&Order{}).Where("id > ?", keygen.Next(24)).Where("user_id", 101).Find(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_005" WHERE "id" > $1 AND "user_id" = $2`, tx)
+	tx := db.Model(&Order{}).Where("id > ?", keygen.Next(1)).Where("user_id", 101).Find(&[]Order{})
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "id" > $1 AND "user_id" = $2`, tx)
 }
 
 func TestSelect9(t *testing.T) {
 	tx := db.Model(&Order{}).Where("user_id = 101").First(&[]Order{})
-	assertQueryResult(t, `SELECT * FROM "orders_005" WHERE "user_id" = 101 ORDER BY "orders_005"."id" LIMIT 1`, tx)
+	assertQueryResult(t, `SELECT * FROM "orders_01" WHERE "user_id" = 101 ORDER BY "orders_01"."id" LIMIT 1`, tx)
 }
 
 func TestSelect10(t *testing.T) {
@@ -167,12 +175,12 @@ func TestSelect13(t *testing.T) {
 
 func TestUpdate(t *testing.T) {
 	tx := db.Model(&Order{}).Where("user_id = ?", 100).Update("product", "new title")
-	assertQueryResult(t, `UPDATE "orders_004" SET "product" = $1 WHERE "user_id" = $2`, tx)
+	assertQueryResult(t, `UPDATE "orders_00" SET "product" = $1 WHERE "user_id" = $2`, tx)
 }
 
 func TestDelete(t *testing.T) {
 	tx := db.Where("user_id = ?", 100).Delete(&Order{})
-	assertQueryResult(t, `DELETE FROM "orders_004" WHERE "user_id" = $1`, tx)
+	assertQueryResult(t, `DELETE FROM "orders_00" WHERE "user_id" = $1`, tx)
 }
 
 func TestInsertMissingShardingKey(t *testing.T) {