MIN中的最小日期

Question

如果在单个查询中可以进行以下操作，我正在努力解决问题。

我们有以下查询从表A和B获取信息

SELECT 
     a.wj_job
     ,a.wj_sched
     ,a.wj_lump
     ,SUM(b.wj_billed) AS wj_billed
     ,SUM(b.wj_received) AS wj_recd
     ,a.wj_lbdate
     ,a.wj_fecom1 
FROM ag_fsch a
     JOIN ag_fschd b ON a.wj_job = b.wj_jbnum AND a.wj_sched = b.wj_sched 
WHERE 
     a.wj_job LIKE "4733.%"
GROUP BY 
     a.wj_job
     ,a.wj_sched 
ORDER BY 
     a.wj_job
     ,a.wj_sched

我想从表b中提取最后一个未付帐单日期作为上述查询的一部分。 下面的查询可以实现相同的功能，但仅适用于原始查询中的特定结果。

SELECT 
     MIN(wj_bdate) 
FROM ag_fschd
WHERE 
     wj_jbnum = 4733.00
     AND wj_sched = 6
     AND wj_billed <> 0
     AND wj_received = 0

Answer 1

我认为你可以使用条件聚合。 我不知道因为有两个按键group by ，而不仅仅是工号。 但是，这可能是您想要的输出：

SELECT a.wj_job, a.wj_sched, a.wj_lump, SUM(b.wj_billed) AS wj_billed,
       SUM(b.wj_received) AS wj_recd, a.wj_lbdate, a.wj_fecom1,
       MIN(CASE WHEN b.wj_sched = 6 AND b.wj_billed <> 0 AND b.wj_received = 0
                THEN wj_bdate
           END)
FROM ag_fsch a JOIN
     ag_fschd b
     ON a.wj_jbnum = b.wj_jbnum AND a.wj_sched = b.wj_sched 
WHERE a.wj_jbnum LIKE '4733.%'
GROUP BY a.wj_jbnum, a.wj_sched 
ORDER BY a.wj_jbnum, a.wj_sched;

Answer 2

使用子查询获取每个的最小日期： -

SELECT a.wj_job, 
        a.wj_sched, 
        a.wj_lump, 
        SUM(b.wj_billed) AS wj_billed,
        SUM(b.wj_received) AS wj_recd, 
        a.wj_lbdate, 
        a.wj_fecom1 ,
        sub0.wj_bdate
FROM ag_fsch a
JOIN ag_fschd b ON a.wj_jbnum = b.wj_jbnum AND a.wj_sched = b.wj_sched 
LEFT OUTER JOIN
(
    SELECT wj_jbnum,
            wj_sched,
            MIN(wj_bdate) 
    FROM ag_fschd
    WHERE wj_billed <> 0
    AND wj_received = 0
    GROUP BY wj_jbnum,
            wj_sched
) sub0
ON sub0.wj_jbnum = a.wj_jbnum AND sub0.wj_sched = a.wj_sched
WHERE a.wj_jbnum LIKE "4733.%"
GROUP BY a.wj_jbnum, a.wj_sched 
ORDER BY a.wj_jbnum, a.wj_sched

请注意，Jarlh在注释中指出，GROUP BY子句有点奇怪，因为它没有所有非聚合字段。 我没有试图解决这个问题。