mysql - 如何找到mysql中某列中缺失的月份？

Question

这是我的 view_remit。我需要确定 month_paid 列中缺少的月份。

我使用此代码来获取此表，但我不知道如何确定丢失的月份。

SELECT RemitNo, PEN, Employer, month_paid, Total_PBR_Amt
FROM view_remit
JOIN (    
        SELECT 'JAN' as month_paid,'2016-01-01' as start,'2016-01-31' as end UNION ALL
        SELECT 'FEB' as month_paid,'2016-02-01' as start,'2016-02-29' as end UNION ALL
        SELECT 'MAR' as month_paid,'2016-03-01' as start,'2016-03-31' as end UNION ALL
        SELECT 'APR' as month_paid,'2016-04-01' as start,'2016-04-30' as end UNION ALL
        SELECT 'MAY' as month_paid,'2016-05-01' as start,'2016-05-31' as end UNION ALL
    SELECT 'JUN' as month_paid,'2016-06-01' as start,'2016-06-30' as end UNION ALL
    SELECT 'JUL' as month_paid,'2016-07-01' as start,'2016-07-31' as end UNION ALL
    SELECT 'AUG' as month_paid,'2016-08-01' as start,'2016-08-31' as end UNION ALL
        SELECT 'SEP' as month_paid,'2016-09-01' as start,'2016-09-30' as end UNION ALL
        SELECT 'OCT' as month_paid,'2016-10-01' as start,'2016-10-31' as end UNION ALL
        SELECT 'NOV' as month_paid,'2016-11-01' as start,'2016-11-30' as end UNION ALL
        SELECT 'DEC' as month_paid,'2016-12-01' as start,'2016-12-31' as end 
    ) M
    ON view_remit.AP_From <= M.end 
   AND view_remit.AP_To >= M.start
ORDER BY PEN, AP_From

我需要得到这个输出。

|PEN|Employer|month|
| 1 |   a    | MAR |
| 1 |   a    | JUN |
| 1 |   a    | JUL |
| 1 |   a    | SEP |
| 1 |   a    | OCT |
| 1 |   a    | NOV |

非常感谢任何帮助。 预先感谢您。

Answer 1

由于我的声誉水平，我仍然无法发表评论。一旦您回答了我的问题，我将立即更正此答案:

• 您能否提供更完整的表格示例:缺少 AP_From 和 AP_To 列。

• 我不明白您如何将“笔”和“雇主”列与缺失的月份链接起来。 无论如何，要根据您表上可用的月份获取缺失的月份，我将按以下步骤操作:

    -- Just for sample query purpose
    IF OBJECT_ID('tempdb..#view_remit') is not null

    DROP TABLE #view_remit
    CREATE TABLE #view_remit (
        RemitNo             INT,
        PEN                 INT,
        Employer            VARCHAR(10),
        wmonth              VARCHAR(3),
        Total_PBR_Amt       FLOAT,
        AP_Date             DATE
    )

    INSERT INTO #view_remit VALUES
    (1,1,'a','JAN',200, '2016-01-20'),
    (1,1,'a','FEV',200, '2016-02-12'),
    (1,1,'a','APR',200, '2016-04-25'),
    (1,1,'a','AUG',200, '2016-08-02'),
    (1,1,'a','DEC',200, '2016-12-24')

    -- Your working month table
    IF OBJECT_ID('tempdb..#table_month') is not null
        DROP TABLE #table_month
    CREATE TABLE #table_month (
        wmonth              VARCHAR(3),
        DateBegin           DATE,
        EndBegin            DATE
    )
    INSERT INTO #table_month VALUES 
    ('JAN', '2016-01-01', '2016-01-31'),
    ('FEV', '2016-02-01', '2016-02-29'),
    ('MAR', '2016-03-01', '2016-03-31'),
    ('APR', '2016-04-01', '2016-04-30'),
    ('MAI', '2016-05-01', '2016-05-31'),
    ('JUN', '2016-06-01', '2016-06-30'),
    ('JUL', '2016-07-01', '2016-07-31'),
    ('AUG', '2016-08-01', '2016-08-31'),
    ('SET', '2016-09-01', '2016-09-30'),
    ('OCT', '2016-10-01', '2016-10-31'),
    ('NOV', '2016-11-01', '2016-11-30'),
    ('DEC', '2016-12-01', '2016-12-31')


    SELECT PEN, Employer, tm.wmonth
    FROM #table_month tm
    LEFT JOIN #view_remit vr
    ON vr.wmonth = tm.wmonth
    WHERE vr.wmonth is null