SQL - 根据 2 个字段查找计数答案

【问题标题】：SQL - find count based on 2 fieldsSQL - 根据 2 个字段查找计数
【发布时间】：2019-12-23 22:57:58
【问题描述】：

我有一个场景，我有 1 张桌子。该表的数据如下：

CATEGORY_TYPE       CATEGORY_TYPE_DESC  RETL_ID
SUPPLIER_XREF       SUPPLIER_XREF       21731
SUPPLIER_SITE_XREF  SUPPLIER_SITE_XREF  21731

我想查找 RETL_ID 出现两次但一条记录属于 SUPPLIER_XREF 而另一条记录属于 SUPPLIER_SITE_XREF 的计数。

我试过了，但这不会返回任何记录。

select RETL_ID, COUNT(*)
FROM RFI_XREF_DVM
WHERE 
CATEGORY_TYPE IN ('SUPPLIER_SITE_XREF') 
AND CATEGORY_TYPE IN ('SUPPLIER_XREF') 
GROUP BY RETL_ID
HAVING COUNT (*) = 2;

【问题讨论】：

标签： sql oracle count duplicates

【解决方案1】：

计算 CATEGORY_TYPE 的不同出现次数：

SELECT RETL_ID, COUNT(DISTINCT CATEGORY_TYPE)
FROM RFI_XREF_DVM
WHERE CATEGORY_TYPE IN ('SUPPLIER_XREF', 'SUPPLIER_SITE_XREF') 
GROUP BY RETL_ID
HAVING COUNT(DISTINCT CATEGORY_TYPE) = 2;

如果您希望 CATEGORY_TYPE 只有这 2 个值而没有其他值：

SELECT RETL_ID, COUNT(DISTINCT CATEGORY_TYPE)
FROM RFI_XREF_DVM
GROUP BY RETL_ID
HAVING 
  COUNT(DISTINCT CATEGORY_TYPE) = 2
  AND
  SUM(CASE WHEN CATEGORY_TYPE NOT IN ('SUPPLIER_XREF', 'SUPPLIER_SITE_XREF') THEN 1 ELSE 0 END) = 0

【讨论】：

【解决方案2】：

select a.RETL_ID, COUNT(*)
FROM RFI_XREF_DVM a, RFI_XREF_DVM b
WHERE 
A.CATEGORY_TYPE IN ('SUPPLIER_SITE_XREF') 
AND b.CATEGORY_TYPE IN ('SUPPLIER_XREF') and a. RETL_ID = b.RETL_ID
GROUP BY a.RETL_ID
HAVING COUNT (*) = 1;

【讨论】：

【解决方案3】：

您可以使用GROUP BY 和HAVING 实现此目的：

SELECT RETL_ID, 
COUNT(1) -- represent 2 for 21731 as per your sample data. If you want it 1 then use distinct retl_id instead of 1 in count
FROM RFI_XREF_DVM
GROUP BY 
RETL_ID
HAVING
SUM(CASE WHEN CATEGORY_TYPE = 'SUPPLIER_XREF' 
THEN 1 END) = 1 AND
SUM(CASE WHEN CATEGORY_TYPE = 'SUPPLIER_SITE_XREF' 
THEN 1 END) = 1

干杯！！

【讨论】：

【解决方案4】：

如果你想要计数，那么一种方法是使用两个级别的聚合：

SELECT COUNT(*)
FROM (SELECT RETL_ID
      FROM RFI_XREF_DVM
      GROUP BY RETL_ID
      HAVING LISTAGG(CATEGORY_TYPE, ',') WITHIN GROUP (ORDER BY CATEGORY_TYPE) = 'SUPPLIER_SITE_XREF,SUPPLIER_XREF'
     ) r;

或者：

SELECT COUNT(*)
FROM (SELECT RETL_ID
      FROM RFI_XREF_DVM
      GROUP BY RETL_ID
      HAVING SUM(CASE WHEN CATEGORY_TYPE = 'SUPPLIER_SITE_XREF' THEN 1 ELSE 0 END) = 1 AND
             SUM(CASE WHEN CATEGORY_TYPE = 'SUPPLIER_XREF' THEN 1 ELSE 0 END) = 1
     ) r;

如果你想要正好两个匹配，你不能在聚合之前过滤。

【讨论】：

【解决方案5】：

如果你想让 RETL_ID 至少出现两次，你可以使用这个：

 select RETL_ID, COUNT(retl_id)
    FROM RFI_XREF_DVM
    WHERE CATEGORY_TYPE in ('SUPPLIER_SITE_XREF', 'SUPPLIER_XREF')
    GROUP BY RETL_ID
    HAVING COUNT(retl_id)>= 2;

如果正好是两次，那么：

select RETL_ID, COUNT(retl_id)
        FROM RFI_XREF_DVM
        WHERE CATEGORY_TYPE in ('SUPPLIER_SITE_XREF', 'SUPPLIER_XREF')
        GROUP BY RETL_ID
        HAVING COUNT(retl_id)= 2;

【讨论】：