Subquery FROM

Use a subquery as the FROM source.

FromSub lets you SELECT from a subquery instead of a table.

Basic usage

sub := Users.From(db).
    Select(Users.Name, dew.As(dew.Count(), "total")).
    GroupBy(Users.Name)

results, err := dew.FromSub[Result](db, sub, "sub").
    Where(dew.Raw("sub.total > ?", 10)).
    All()
// SELECT * FROM (SELECT users.name, COUNT(*) AS total FROM users GROUP BY users.name) AS sub
// WHERE sub.total > $1

With set operations

admins := Users.From(db).Select(Users.Name).Where(Users.Role.Eq("admin"))
mods := Users.From(db).Select(Users.Name).Where(Users.Role.Eq("mod"))
combined := dew.UnionAll[User](db, admins, mods)

results, err := dew.FromSub[User](db, combined, "staff").All()
// SELECT * FROM (...UNION ALL...) AS staff

Constructor

func FromSub[T any](db Querier, subQuery Expression, alias string) *Selector[T]

subQuery — any Expression (a Selector, SetQuery, or Raw)
alias — the alias for the derived table (required by SQL)

Set Operations

UNION, UNION ALL, INTERSECT, and EXCEPT.

Transactions

Run queries in a transaction.

On this page

Basic usage With set operations Constructor