SQL在应该提取值时提取null

我以前就有这个功能,我一辈子都搞不清楚它发生了什么,因为它不会显示Q4和Q5列的真实值。

此查询正在提取调查数据,所有行的Q4和Q5都为空。第一季度至第三季度的数据显示正确。

这是我的疑问:

DECLARE @start as datetime2(0) = '2021-01-01'

SELECT
    MAX(IIF(metric.name = 'Q1' AND survey.sr_actual_value BETWEEN 1 AND 5, survey.sr_actual_value, NULL)) AS Q1,
    MAX(IIF(metric.name = 'Q2' AND survey.sr_actual_value BETWEEN 1 AND 5, survey.sr_actual_value, NULL)) AS Q2,
    MAX(IIF(metric.name = 'Q3' AND survey.sr_actual_value BETWEEN 1 AND 5, survey.sr_actual_value, NULL)) AS Q3,
    MAX(IIF(metric.name = 'Q4' AND survey.sr_actual_value BETWEEN 1 AND 5, survey.sr_actual_value, NULL)) AS Q4,
    MAX(IIF(metric.name = 'Q5' AND survey.sr_actual_value BETWEEN 1 AND 5, survey.sr_actual_value, NULL)) AS Q5,
    MAX(IIF(metric.name = 'Q6', survey.sr_string_value, NULL)) AS Comment,
    MAX(survey.si_taken_on) as Taken,
    MAX(ims.number) as [Number],
    MAX(ims.sys_id) as sys_id,
    MAX(tech.name) AS Tech,
    MAX(man.first_name) AS Manager,
    MAX(cust.name) AS Customer,
    CASE
    WHEN MAX(awi.queue) = 'b63d965cdbb05454586593a6f4961968' THEN 'SS'
    WHEN MAX(awi.queue) = '67e1f6cbdb9298548fd6695e1396199c' THEN 'Chat'
    ELSE NULL
    END as [Group]

FROM [v2_sn].[u_interaction_survey_reporting] as survey

LEFT JOIN v2_sn.sys_user as cust on cust.sys_id = survey.si_user
LEFT JOIN v2_sn.asmt_metric as metric on metric.sys_id = survey.sr_metric
LEFT JOIN v2_sn.interaction as ims on ims.sys_id = survey.inter_sys_id
LEFT JOIN v2_sn.sys_user as tech on tech.sys_id = ims.assigned_to
LEFT JOIN v2_sn.sys_user as man on man.sys_id = tech.manager
left join v2_sn.awa_work_item as awi on awi.document_id = ims.sys_id

WHERE survey.si_taken_on >= @start
    and metric.name in ('Q1','Q2','Q3','Q4''Q5','Q6')
    and survey.si_metric_type = '1c4f20afdbc614103779a6dc139619c9'
    and awi.queue in ('b63d965cdbb05454586593a6f4961968', '67e1f6cbdb9298548fd6695e1396199c')

GROUP BY survey.si_sys_id

就像我说的,它以前是有效的。我试着改变日期,看看这是不是2021个问题,这无济于事。我确认数据库包含Q4和Q5数据,并且不应为空。有人知道这里发生了什么吗?任何帮助都将不胜感激。如果您需要更多信息或有疑问,请不要犹豫。