GoFrame 數(shù)據(jù)查詢-Union/UnionAll

?GoFrame ORM? 組件支持?Union/UnionAll?操作，?Union/UnionAll?操作符用于連接兩個(gè)以上的SELECT語句的結(jié)果組合到一個(gè)結(jié)果集合中，關(guān)于?Union/UnionAll?組合查詢的相關(guān)介紹可以參考?MySQL?的官方文檔介紹 https://dev.mysql.com/doc/refman/8.0/en/union.html 。我們可以通過鏈?zhǔn)讲僮骰蛘叻椒ú僮鱽韺?shí)現(xiàn)?Union/UnionAll?操作。

方法定義

// Union does "(SELECT xxx FROM xxx) UNION (SELECT xxx FROM xxx) ..." statement.
func (c *Core) Union(unions ...*Model) *Model

// UnionAll does "(SELECT xxx FROM xxx) UNION ALL (SELECT xxx FROM xxx) ..." statement.
func (c *Core) UnionAll(unions ...*Model) *Model

Union

使用?Union?操作符，多個(gè)SELECT語句會(huì)刪除重復(fù)的數(shù)據(jù)。

// 獲取默認(rèn)配置的數(shù)據(jù)庫對象(配置名稱為"default")
db := g.DB()

db.Union(
    db.Model("user").Where("id", 1),
    db.Model("user").Where("id", 2),
    db.Model("user").WhereIn("id", g.Slice{1, 2, 3}),
).OrderDesc("id").All()
// (SELECT * FROM `user` WHERE `id`=1) 
// UNION 
// (SELECT * FROM `user` WHERE `id`=2) 
// UNION 
// (SELECT * FROM `user` WHERE `id` IN (1,2,3) 
// ORDER BY `id` DESC) ORDER BY `id` DESC 

也可以通過?dao?鏈?zhǔn)讲僮鲗?shí)現(xiàn)：

dao.User.Union(
    dao.User.Where(dao.User.Columns.Id, 1),
    dao.User.Where(dao.User.Columns.Id, 2),
    dao.User.WhereIn(dao.User.Columns.Id, g.Slice{1, 2, 3}),
).OrderDesc(dao.User.Columns.Id).All()
// (SELECT * FROM `user` WHERE `id`=1) 
// UNION 
// (SELECT * FROM `user` WHERE `id`=2) 
// UNION 
// (SELECT * FROM `user` WHERE `id` IN (1,2,3) 
// ORDER BY `id` DESC) ORDER BY `id` DESC 

UnionAll

使用?UnionAll?操作符，多個(gè)SELECT?語句不會(huì)刪除重復(fù)的數(shù)據(jù)。

db.UnionAll(
    db.Model("user").Where("id", 1),
    db.Model("user").Where("id", 2),
    db.Model(table).WhereIn("id", g.Slice{1, 2, 3}),
).OrderDesc("id").All()
// (SELECT * FROM `user` WHERE `id`=1) 
// UNION ALL 
// (SELECT * FROM `user` WHERE `id`=2) 
// UNION ALL 
// (SELECT * FROM `user` WHERE `id` IN (1,2,3) 
// ORDER BY `id` DESC) ORDER BY `id` DESC 

也可以通過?dao?鏈?zhǔn)讲僮鲗?shí)現(xiàn)：

dao.User.UnionAll(
    dao.User.Where(dao.User.Columns.Id, 1),
    dao.User.Where(dao.User.Columns.Id, 2),
    dao.User.WhereIn(dao.User.Columns.Id, g.Slice{1, 2, 3}),
).OrderDesc(dao.User.Columns.Id).All()
// (SELECT * FROM `user` WHERE `id`=1) 
// UNION ALL 
// (SELECT * FROM `user` WHERE `id`=2) 
// UNION ALL 
// (SELECT * FROM `user` WHERE `id` IN (1,2,3) 
// ORDER BY `id` DESC) ORDER BY `id` DESC