sql - "SELECT INTO"是做什么的？

Question

我正在阅读 sql 代码，其中一行看起来像这样:

SELECT INTO _user tag FROM login.user WHERE id = util.uuid_to_int(_user_id)::oid;

这到底是做什么的？使用 SELECT INTO 的通常方法需要在 SELECT 标记之后指定要选择的列，例如

SELECT * INTO _my_new_table WHERE ...;

数据库是postgresql。

Answer 1

这一行必须出现在 PL/pgSQL 函数中。在这种情况下，tag 列的值被分配给变量 _user。

根据documentation :

Tip: Note that this interpretation of SELECT with INTO is quite different from PostgreSQL's regular SELECT INTO command, wherein the INTO target is a newly created table.

和

The INTO clause can appear almost anywhere in the SQL command. Customarily it is written either just before or just after the list of select_expressions in a SELECT command, or at the end of the command for other command types. It is recommended that you follow this convention in case the PL/pgSQL parser becomes stricter in future versions.