sql-server - 将 SQL "Not In"更改为 "Left Outer Join"

Question

我不想在这个 sql 查询中使用“not in”。我该怎么做？谢谢

SELECT  
 T2.Sno,
 T2.Name,
 T1.description,
 T2.UserCode            
FROM 
 Table1 AS T1 (nolock)
    INNER JOIN T2 (nolock)
    ON T1.UserCode = T2.UserCode
WHERE
 g.xid= @p_xid
 and T2.Sno not in (select Gid from T3 (nolock))

Answer 1

假设 T2 中不存在 Sno 为 null 且 T3 中 Gid 为 null 的行:

SELECT  
 T2.Sno,
 T2.Name,
 T1.description,
 T2.UserCode            
FROM 
 Table1 AS T1 WITH (nolock)
    INNER JOIN T2 WITH (nolock)
      LEFT JOIN T3 WITH (NOLOCK)
      ON T2.Sno = T3.Gid
    ON T1.UserCode = T2.UserCode
WHERE
 g.xid= @p_xid
 and T3.Gid IS NULL