查詢返回ORA-00936：缺少表達

Question

我運行下面的查詢，試圖找到第一次插入行的重複實例的存在： -

SELECT COUNT(*) 
    FROM rlx_service_info 
    WHERE row(personalaccountid,serviceid,serviceline, 
       userserviceid,servicerf) IN (SELECT personalaccountid, 
                serviceid, 
                serviceline, 
                userserviceid, 
                servicerf 
              FROM rlx_service_info 
              WHERE masteraccountid = 'x' 
               AND status   = 30 
               AND rownum   =1 
              ORDER BY startdate); 

Answer 1

您可以使用分析功能（無需第二個表掃描）的所有重複的行：

SELECT * 
FROM (
    SELECT r.*, 
     ROW_NUMBER() 
      OVER (
      PARTITION BY personalaccountid, 
          serviceid, 
          serviceline, 
          userserviceid, 
          servicerf 
      ORDER BY  startdate 
      ) as rn, 
     COUNT(CASE WHEN masteraccountid = 'x' AND status = 30 THEN 1 END) 
      OVER (
      PARTITION BY personalaccountid, 
          serviceid, 
          serviceline, 
          userserviceid, 
          servicerf 
      ) as ct 
    FROM rlx_service_info r 
) 
WHERE ct > 0 
AND rn > 1; 

如果你只是想的計數，然後將外部查詢更改爲：

SELECT COUNT(*) 
FROM (
    SELECT COUNT(CASE WHEN masteraccountid = 'x' AND status = 30 THEN 1 END) 
      OVER (
      PARTITION BY personalaccountid, 
          serviceid, 
          serviceline, 
          userserviceid, 
          servicerf 
      ) as ct 
    FROM rlx_service_info r 
) 
WHERE ct > 0; 

Answer 2

要解決的語法，你必須刪除row和order by條款。 此外，如果子查詢只給一個行（rownum = 1）你不需要一個IN：

SELECT COUNT(*) 
    FROM rlx_service_info 
WHERE (personalaccountid, 
     serviceid, 
     serviceline, 
     userserviceid, 
     servicerf) = ( SELECT personalaccountid, 
           serviceid, 
           serviceline, 
           userserviceid, 
           servicerf 
          FROM rlx_service_info 
          WHERE  masteraccountid = 'x' 
           AND status = 30 
           AND ROWNUM = 1) 

例如：

SQL> select 1 
    2 from dual 
    3 where (1, 2) in (select 1, 2 from dual); 

     1 
---------- 
     1 

SQL> select 1 
    2 from dual 
    3 where row(1, 2) in (select 1, 2 from dual); 
where row(1, 2) in (select 1, 2 from dual) 
       * 
ERROR at line 3: 
ORA-00936: missing expression 

但是，如果你需要的子查詢只返回一行與最低startDate，認爲order by結合rownum條件不是一種方式;你會發現許多關於如何做到這一點的好答案。

例如：

SQL> select * 
    2 from (
    3   select 1 x from dual union all 
    4   select 2 x from dual 
    5  ) 
    6 where rownum = 1 
    7 order by x; 

     X 
---------- 
     1 

SQL> select * 
    2 from (
    3   select 2 x from dual union all 
    4   select 1 x from dual 
    5  ) 
    6 where rownum = 1 
    7 order by x; 

     X 
---------- 
     2