postgresql 将字段与值进行比较并返回布尔值

Compare field with value and return bool

提问by Arman Hayots

I'm trying move hash cheking from server app to PostgreSQL. In other words I'm need calling a query to PGSQL, which compare string from query with string from field and return result of equal comparison as bool, but I don't know how do this without procedures on clear SQL.

我正在尝试将哈希检查从服务器应用程序移动到 PostgreSQL。换句话说，我需要向 PGSQL 调用一个查询，它将查询中的字符串与字段中的字符串进行比较，并将相等比较的结果返回为 bool，但我不知道如果没有清除 SQL 的过程，我该怎么做。

upd: I have table userswith field password(currently text, in the future - bytea). I want write sometihng like

upd：我有带有字段密码的表用户（当前为text，将来为bytea）。我想写点东西

select * from values ('WrittenPassword' = users.password) where username = 'someuser' ,

which must return true or false as result of equal comparison.

作为相等比较的结果，它必须返回 true 或 false。

回答by Zane Bien

You can use a CASEstatement to return certain values based on a condition:

您可以使用CASE语句根据条件返回某些值：

SELECT 
    (CASE WHEN password = 'WrittenPassword' THEN 1 ELSE 0 END) AS is_equal
FROM
    users
WHERE
    username = 'someuser'