使用临时表将 T-SQL 转换为 MySQL

Question

我正在将 T-SQL 存储过程转换为 MySQL。我不熟悉 T-SQL，并且正在努力变得更加熟悉临时表和存储过程。提前感谢您的帮助。

T-SQL 原始文件如下所示（编辑： 注意这只是用于生成报告的原始过程的一部分）：

DROP TABLE IF EXISTS #accounts;

SELECT  d.data_id                   
        ,p.pp_name AS name
        ,CONVERT(tinyint,1) AS flag             
        ,d.pd_date
        ,CONVERT(char(6),pd_date,112) AS date_period                
        ,CONVERT(varchar(3),0) AS n_phones                          
INTO    #accounts                   
from    table_detail d                  
    JOIN    table_pool p ON d.pp_id = p.pp_id                   
    JOIN    table_type t ON p.pp_type_id = t.pp_type_id                                                     
    JOIN    Inventory i ON d.data_id = i.data_id                    
    JOIN    Product pr ON i.product_id = pr.product_id  
WHERE   pp_name IN (SELECT name FROM Sandbox..desired_sandbox)                  
    AND DATEDIFF(MONTH,pd_date,GETDATE()) < 3
            
                        
UPDATE  a                   
SET     a.flag = 0              
FROM    #accounts a                 
JOIN    table_detail d ON a.data_id = d.data_id                 
JOIN    table_pool p ON d.pp_id = p.pp_id                   
WHERE   d.pd_date < a.pd_date                   
    AND pp_name != 'error';     

我当前的更新如下。我是否需要将其包装在 CREATE TEMPORARY TABLE IF NOT EXISTS accounts AS (<insert query here>) 而不是 INTO #accounts 中？

SELECT  d.data_id                   
        ,p.pp_name AS name                              
        ,CONVERT(tinyint,1) AS flag             
        ,d.pd_date
        ,DATE_FORMAT(pd_date,'%Y%m%d') AS date_period               
        ,CONVERT(varchar(3),0) AS n_phones                                  
FROM    table_detail d                  
    JOIN    table_pool p ON d.pp_id = p.pp_id                   
    JOIN    table_type t ON p.pp_type_id = t.pp_type_id                                 
    JOIN    Inventory i ON d.data_id = i.data_id                    
    JOIN    Product pr ON i.product_id = pr.product_id  
WHERE   pp_name IN (SELECT name FROM Sandbox..desired_sandbox)              
    AND TIMESTAMPDIFF(MONTH,pd_date,NOW()) < 3

假设语法正确，然后执行以下操作：

UPDATE  accounts a -- Is this the correct way to add an alias and update the temp table?                
    JOIN    table_detail d ON a.data_id = d.data_id                 
    JOIN    table_pool p ON d.pp_id = p.pp_id                   
SET     a.flag = 0              
WHERE   d.pd_date < a.pd_date                   
    AND pp_name != 'error'; 

最后，我假设我可以按照this post 将最终查询包装到存储过程中，对吗？总结一下帖子中的代码：

drop procedure if exists procedure_name;
DELIMITER $$
create procedure procedure_name ()
BEGIN
    DROP TEMPORARY TABLE IF EXISTS accounts;

    CREATE TEMPORARY TABLE accounts AS (
    SELECT...
    FROM...
    WHERE...
    ;
    )

    UPDATE accounts
        JOIN ...
        JOIN ...
    SET...
    WHERE...;
    
    DROP TEMPORARY TABLE accounts; -- otherwise it survives the stored proc call
END
$$ -- signify end of block
DELIMITER ; -- reset to default delimiter

Answer 1

我想为可能遇到相同问题的其他人发布最终对我有用的解决方案。下面的代码解决了这个问题。

DROP PROCEDURE IF EXISTS procedure_name;

DELIMITER $$

CREATE PROCEDURE procedure_name ()
BEGIN
    DROP TEMPORARY TABLE IF EXISTS accounts;

    CREATE TEMPORARY TABLE accounts AS (
        SELECT  d.data_id                   
               ,p.pp_name AS name                              
               ,1 AS flag             
               ,d.pd_date
               ,DATE_FORMAT(pd_date,'%Y%m%d') AS date_period               
               ,CONVERT(varchar(3),0) AS n_phones                                  
       FROM    table_detail d                  
           JOIN    table_pool p ON d.pp_id = p.pp_id                   
           JOIN    table_type t ON p.pp_type_id = t.pp_type_id                                 
           JOIN    Inventory i ON d.data_id = i.data_id                    
           JOIN    Product pr ON i.product_id = pr.product_id  
       WHERE   pp_name IN (SELECT name FROM Sandbox..desired_sandbox)              
           AND TIMESTAMPDIFF(MONTH,pd_date,NOW()) < 3
    
    );
    
    -- Update the temp table based on specified criteria
    UPDATE accounts
        JOIN ...
        JOIN ...
    SET...
    WHERE...;

    -- Create final Query for report
    SELECT ...
    FROM accounts
    WHERE ...
    GROUP BY ... -- whatever you need for final query
    
    DROP TEMPORARY TABLE accounts; -- otherwise it survives the stored proc call
END
$$ -- signify end of block
DELIMITER ; -- reset to default delimiter

但是，重要的是要注意 MySQL 临时表的限制。虽然我没有在我的原始帖子中指出它，但后来，我试图将临时表加入到自身中。我需要遵循here 概述的建议。本质上，如果您需要自己引用临时表，则需要制作临时表的副本：CREATE TEMPORARY TABLE accounts2 AS (SELECT * FROM accounts)。然后你可以将一个临时表加入到自身中。