Question

  DECLARE @source as NVARCHAR(MAX) = (SELECT md.[source] FROM sports_service.meet.meet_detail md WHERE md.meet_id = #{meetId})

    WHERE reg.is_waitlist = 0 AND reg.cancelled_dt IS NULL 
          AND NOT EXISTS (
            SELECT 1 FROM sports_service.meet.meet_invitations i
            WHERE i.meet_id = pmm.meet_id AND i.sports_person_id = reg.sports_person_id) 
     IF @source != 'MANUAL'
          AND EXISTS (
            SELECT 1 
            FROM sports_service.meet.session session
                INNER JOIN sports_service.meet.event event ON event.session_id = session.id 
                WHERE pmm.meet_id = session.meet_id
                    AND sports_service.dbo.fnGetMeetAge(p.birth_dt, detail.age_up_date, detail.id_format) <![CDATA[>=]]> event.low_age
                    AND sports_service.dbo.fnGetMeetAge(p.birth_dt, detail.age_up_date, detail.id_format) <![CDATA[<=]]> event.high_age
                    AND (event.eligible_gender IS NULL OR event.eligible_gender = p.gender))

Answer 1

如果您仅在满足其他条件（源为AND EXISTS ...）并且要在一个查询中而不是：

时才要检查某个条件（MANUAL子句），

WHERE (...some condition ...) AND (.. some other condition ... )
IF @source != 'MANUAL'
    AND EXISTS (
        SELECT 1 ... )

不支持，因为它不是正确的sql语法，您可以执行以下操作：

WHERE (...some condition ...) AND (.. some other condition ... )
    AND (
       (
         (SELECT md.[source] 
          FROM sports_service.meet.meet_detail md 
          WHERE md.meet_id = #{meetId}
         ) = 'MANUAL'
       )
      OR EXISTS (
        SELECT 1 
        FROM ...
      )
    )

您需要检查结果查询的性能是否令人满意。

最好执行先获取source的查询，然后再根据附加条件source执行带有附加条件或不附加条件的查询。为此，您可以使用dynamic SQL（包括或排除此附加条件）在mybatis中生成查询。

Answer 2

由于不能使用If表达式，因此可以这样编写sql：

DECLARE @source as NVARCHAR(MAX) = (SELECT md.[source] FROM sports_service.meet.meet_detail md WHERE md.meet_id = #{meetId})

    WHERE reg.is_waitlist = 0 AND reg.cancelled_dt IS NULL
    AND NOT EXISTS (
    SELECT
    1
    FROM
    sports_service.meet.meet_invitations i
    WHERE
    i.meet_id = pmm.meet_id
    AND i.sports_person_id = reg.sports_person_id)
    AND ( @source <> 'MANUAL' 
    AND 
    EXISTS ( SELECT 1 FROM
    sports_service.meet.session session
    INNER JOIN sports_service.meet.event event ON
    event.session_id = session.id
    WHERE
    pmm.meet_id = session.meet_id
    AND sports_service.dbo.fnGetMeetAge(p.birth_dt,
    detail.age_up_date,
    detail.id_format) >= event.low_age
    AND sports_service.dbo.fnGetMeetAge(p.birth_dt,
    detail.age_up_date,
    detail.id_format) <= event.high_age
    AND (event.eligible_gender IS NULL
    OR event.eligible_gender = p.gender)))

Answer 3

您不能在表达式内使用IF。

'）'附近的语法不正确。在DBeaver和Java映射器文件上运行时，SQL查询错误？

3 个答案: