搜索

首页  >  问答  >  正文

我想排除不属于 case when 语句中指定的值范围的记录 - SQL/MySQL

我正在尝试为来自 DTBL_SCHOOL_DATES 表的特定日期设置季节范围。以下是我的逻辑,它根据年份及其地区来设置给定范围内的季节。

CASE 
        WHEN RTRIM(dtbl_school_dates.local_school_year) = '2021-2022' THEN 
            CASE 
                WHEN RTRIM(dtbl_schools_ext.region) = 'Bay Area' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '08/07/2021' and '09/08/2021' THEN 'FALL'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Bay Area' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '11/27/2021' and '12/15/2021' THEN 'WINTER'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Bay Area' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '03/04/2022' and '03/22/2022' THEN 'SPRING'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Central Valley' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '07/31/2021' and '09/01/2021' THEN 'FALL'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Central Valley' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '11/27/2021' and '12/15/2021' THEN 'WINTER'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Central Valley' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '02/19/2022' and '03/08/2022' THEN 'SPRING'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Los Angeles' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '08/14/2021' and '09/15/2021' THEN 'FALL'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Los Angeles' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '11/27/2021' and '12/15/2021' THEN 'WINTER'
                WHEN RTRIM(dtbl_schools_ext.region) = 'Los Angeles' AND 
                    CAST(dtbl_school_dates.date_value AS DATE) BETWEEN '03/04/2022' and '03/22/2022' THEN 'SPRING' 
                ELSE 'NOT IN RANGE' 
            END 
        ELSE FTBL_TEST_SCORES.test_admin_period 
    END AS "C4630"

但是每当日期不在逻辑中指定的范围内时,我希望它们被忽略。又名“不在范围内”的值应该被排除。我尝试使用 FTBL_TEST_SCORES.test_admin_period 不为空,并且由于数据库中没有值为空,它们将无法工作。

不在范围内的值应该被排除在结果中,我如何在 where 子句中实现这一点

我尝试使用 Alias 进行限制,但不起作用。 我不确定是否可以将值分配给 case 语句中的特定字段,例如 Case when 'a' then field ='B' end

不在范围内的值应该被排除在结果中,我如何在 where 子句中实现这一点

P粉428986744P粉428986744443 天前591

全部回复(2)我来回复

  • P粉083785014

    P粉0837850142023-09-12 16:42:13

    如果无法查看完整的查询,就不可能提出最佳解决方案。最简单的解决方案是将标准添加为 HAVING 子句:

    HAVING `C4630` <> 'NOT IN RANGE'
    

    我对你的日期格式感到困惑。如果这应该是 MySQL 查询,则它们应该采用 yyyy-mm-dd 格式。可以说,即使在支持不明确的本地日期格式的 SQL Server 上,它们也应该采用这种格式。

    为什么都是RTRIMCAST?数据应该以正确的格式存储,并在输入时进行清理,如果无法做到这一点,请定期清理数据,而不是对每个查询都进行清理。

    明智的做法是将您的季节移动到它们自己的表中,而不是在查询时定义它们。然后它是一个简单的连接到seasons。我在这里使用了子查询,但希望您能明白:

    SELECT
        /* other columns */
        COALESCE(seasons.season, FTBL_TEST_SCORES.test_admin_period) AS `C4630`
    FROM all_the_other_tables
    LEFT JOIN (
    
        SELECT 'Bay Area' AS region, 'FALL' AS season, '2021-08-07' AS start, '2021-09-08' AS end UNION ALL
        SELECT 'Bay Area'          , 'WINTER'        , '2021-11-27'         , '2021-12-15'        UNION ALL
        SELECT 'Bay Area'          , 'SPRING'        , '2022-03-04'         , '2022-03-22'        UNION ALL
            
        SELECT 'Central Valley'    , 'FALL'          , '2021-07-31'         , '2021-09-01'        UNION ALL
        SELECT 'Central Valley'    , 'WINTER'        , '2021-11-27'         , '2021-12-15'        UNION ALL
        SELECT 'Central Valley'    , 'SPRING'        , '2022-02-19'         , '2022-03-08'        UNION ALL
            
        SELECT 'Los Angeles'       , 'FALL'          , '2021-08-14'         , '2021-09-15'        UNION ALL
        SELECT 'Los Angeles'       , 'WINTER'        , '2021-11-27'         , '2021-12-15'        UNION ALL
        SELECT 'Los Angeles'       , 'SPRING'        , '2022-03-04'         , '2022-03-22'
    
    ) AS seasons
        ON dtbl_school_dates.local_school_year = '2021-2022'
        AND dtbl_schools_ext.region = seasons.region
        AND dtbl_school_dates.date_value BETWEEN seasons.start AND seasons.end
    WHERE (
        (dtbl_school_dates.local_school_year = '2021-2022' AND seasons.season IS NOT NULL) OR
        dtbl_school_dates.local_school_year <> '2021-2022'
    );
    

    回复
    0
  • P粉718165540

    P粉7181655402023-09-12 13:39:57

    您可以在 WHERE 子句中重复整个 CASE 语句,如下所示:

    select
        case
            when x then y 
            when a then b 
            when c then d 
            else 'NOT IN RANGE'
        end as foo
    from
        table t 
    where 
        case
            when x then y 
            when a then b 
            when c then d 
            else 'NOT IN RANGE'
        end <> 'NOT IN RANGE'

    或者您可以使用子查询(或 CTE),如下所示:

    select * 
    from (
        select
            case
                when x then y 
                when a then b 
                when c then d 
                else 'NOT IN RANGE'
            end as foo
        from
            table t 
    ) 
    where foo <> 'NOT IN RANGE'

    回复
    0
  • 取消回复