从查询中返回类似错误代码的内容

Question

我想检查查询中的条件。如果条件为假，则查询必须 returns 错误代码，否则查询必须执行另一个查询。

类似的东西：

WITH error_code_get AS (
    SELECT 
    CASE 
        WHEN NOT EXISTS (
            SELECT 1 
            FROM users 
            WHERE id = '1a4b...'
        ) THEN 1
    
        WHEN NOT EXISTS (
            SELECT 1
            FROM workspaces
            WHERE id = '353...'
        ) THEN 2
    
       WHEN (
            SELECT settings
            FROM workspace_roles 
            WHERE workspace_id = '353...'
            AND id IN (
                SELECT role_id 
                FROM m2m_users_to_workspace_or_projects_roles 
                WHERE role_type='1' 
                AND user_id='1a4b...'
           )
        ) < 2 THEN 3
    
        ELSE 0

    END error_code

    RETURNING error_code

)
// WRONG PART
CASE 
    WHEN (SELECT error_code FROM error_code_get) = 0 THEN (INSERT INTO x(a) VALUES('some_value')) 
    ELSE (SELECT error_code FROM error_code_get)
END

Answer 1

你不能在纯 SQL 中做类似的事情，你需要在存储过程或函数中编写代码

从查询中返回类似错误代码的内容

Returning something like error-codes from query

sql

postgresql

case