如何将此代码从 SQL SERVER 解析到 POSTGRESQL？

Question

如何将此代码从 SQL SERVER 解析到 POSTGRESQL？

SELECT A.GroupNo
             , A.AuthorityGroupName
             , STUFF((SELECT ', ' + C.CodeName
                       FROM TUserAuthority B 
                      INNER JOIN TDetailCode C 
                         ON B.UserType = C.CodeValue
                      WHERE B.DeleteYesNo = 'N'
                        AND B.GroupNo = A.GroupNo
                        FOR XML PATH('')), 1, 2, '') AS UserTypeArray
             , A.UseYesNo
          FROM TAuthorityGroup A 
         WHERE A.DeleteYesNo = 'N';

Answer 1

您的 SQL Server 查询正在执行旧式组连接。 从 Postgres 9+ 我们可以简单地使用STRING_AGG ：

SELECT a.GroupNo,
       a.AuthorityGroupName,
       a.UseYesNo,
       STRING_AGG(c.CodeName, ', ') AS UserTypeArray
FROM TAuthorityGroup a
LEFT JOIN TUserAuthority b
    ON b.GroupNo = a.GroupNo AND
       b.DeleteYesNo = 'N'
LEFT JOIN TDetailCode c
    ON b.UserType = c.CodeValue
WHERE
    a.DeleteYesNo = 'N'
GROUP BY
    a.GroupNo,
    a.AuthorityGroupName,
    a.UseYesNo;