Question

对于表中不存在的行，我想为MAX_TIER返回0

到目前为止，这是我的代码：

SELECT   
    LAST_YARD_BAY, LAST_YARD_ROW, MAX(LAST_YARD_TIER) as MAX_TIER
FROM
    Handlift
WHERE 
    HDCHKOUTD_OUT IS NULL 
    AND LIFLAG = 'A'
    AND LAST_YARD_PARK = 'J1'
GROUP BY 
    LAST_YARD_BAY, LAST_YARD_ROW
ORDER BY 
    LAST_YARD_BAY, LAST_YARD_ROW;

屏幕截图显示了部分结果：

对于海湾005，我有MAX_TIER，行00A至00G，但是对于海湾007，我只有3行：00E ，00F和00G。

对于海湾{{1}的4个缺失行（MAX_TIER，00A，00B和00C，如何为00D填充值为0的值}}和其他缺少的行？

Answer 1

使用CROSS JOIN生成行，使用LEFT JOIN生成结果：

SELECT lyb.LAST_YARD_BAY, lyr.LAST_YARD_ROW, 
       COALESCE(MAX(LAST_YARD_TIER), 0) as MAX_TIER
FROM (SELECT DISTINCT LAST_YARD_BAY FROM Handlift) lyb CROSS JOIN
     (SELECT DISTINCT LAST_YARD_ROW FROM Handlift) lyr LEFT JOIN
     Handlift hl
     ON hl.LAST_YARD_BAY = lyb.LAST_YARD_BAY AND
        hl.LAST_YARD_ROW = lyr.LAST_YARD_ROW AND
        hl.HDCHKOUTD_OUT IS NULL AND
        hl.LIFLAG = 'A' AND
        hl.LAST_YARD_PARK = 'J1'
GROUP BY lyb.LAST_YARD_BAY, lyr.LAST_YARD_ROW
ORDER BY lyr.LAST_YARD_BAY, lyr.LAST_YARD_ROW;

我不确定过滤应该如何工作。您可能希望将结果限制在子查询中，以便它们过滤您获得的托架和行。

Answer 2

您在寻找什么吗？

SELECT *
FROM T
WHERE LastYardBay = '005'
UNION
SELECT '007',
       T1.LastYardRow,
       ISNULL(T2.MaxTier, 0)
FROM 
    (
      SELECT *
      FROM T
      WHERE LastYardBay = '005'
    ) T1
    LEFT JOIN
    (
      SELECT *
      FROM T
      WHERE LastYardBay = '007'
    ) T2
ON T1.LastYardRow = T2.LastYardRow;

返回：

+-------------+-------------+---------+
| LastYardBay | LastYardRow | MaxTier |
+-------------+-------------+---------+
|         005 | 00A         |       3 |
|         005 | 00B         |       4 |
|         005 | 00C         |       1 |
|         005 | 00D         |       1 |
|         005 | 00E         |       1 |
|         005 | 00F         |       4 |
|         005 | 00G         |       1 |
|         007 | 00A         |       0 |
|         007 | 00B         |       0 |
|         007 | 00C         |       0 |
|         007 | 00D         |       0 |
|         007 | 00E         |       5 |
|         007 | 00F         |       4 |
|         007 | 00G         |       1 |
+-------------+-------------+---------+

Live Demo

更新：

由于您已经拥有'005'，因此只需要一个CROSS JOIN，然后使用IS NULL进行过滤

WITH A AS
(
SELECT       T1.LastYardBay LYB1,
             T1.LastYardRow LYR1,
             T1.MaxTier MT1,
             T2.LastYardBay LYB2,
             T2.LastYardRow LYR2,
             T2.MaxTier MT2
FROM 
    (
      SELECT *
      FROM T
      WHERE LastYardBay = '005'
    ) T1
    CROSS JOIN
    (
      SELECT *
      FROM T
      WHERE LastYardBay != '005'
    ) T2
)
SELECT *
FROM T
WHERE LastYardBay = '005'
UNION
SELECT  LYB2,
        LYR1,   
        CASE WHEN LYR2 = LYR1 THEN MT2 ELSE 0 END MT
FROM A LEFT JOIN T ON A.LYB2 IS NULL;

SQL Server：对于不存在的行，用0填充MAX（列）值

2 个答案: