Columns
The orm.Columns
type is a bob expression.
To create a new columns list, use orm.NewColumns(names ...string)
. You can then add the parent table with WithParent()
orm.NewColumns("id", "name", "email").WithParent("public.users")
-- table_alias.column_name
"public.users"."id" AS "id",
"public.users"."name" AS "name",
"public.users"."email" AS "email"
It has many convenient methods to manipulate the columns list.
Only
Returns the column list with ONLY the given column names.
userView.Columns().Only("email")
"public.users"."email" AS "email",
Except
Returns the columns list w ithout the given column names.
userView.Columns().Except("email")
"public.users"."id" AS "id",
"public.users"."name" AS "name",
WithParent
Changes the parent of the column list. For example if selecting with an alias.
Multiple strings are quoted and joined with a dot.
userView.Columns().WithParent("backup", "users_old")
"backup"."users_old"."id" AS "id",
"backup"."users_old"."name" AS "name",
"backup"."users_old"."email" AS "email"
WithPrefix
Sets a prefix for all columns, useful for joins with duplicate column names.
userView.Columns().WithPrefix("users.")
"public.users"."id" AS "users.id",
"public.users"."name" AS "users.name",
"public.users"."email" AS "users.email"