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Version: 2.8.x(Latest)

GoFrame ORM component supports Union/UnionAll operations, where the Union/UnionAll operator is used to combine the results of two or more SELECT statements into a single result set. For more information on Union/UnionAll composite queries, refer to the MySQL official documentation https://dev.mysql.com/doc/refman/8.0/en/union.html. We can achieve Union/UnionAll operations through chaining operations or method operations.

Method Definition​

// 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​

Using the Union operator, multiple SELECT statements will remove duplicate data.

// Get the default configured database object (configuration name is "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

It can also be implemented through dao chaining operations:

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​

Using the UnionAll operator, multiple SELECT statements will not remove duplicate data.

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

It can also be implemented through dao chaining operations:

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