DateAdd() 中的嵌套 SELECT 语句

Question

我正在尝试获取列的 MAX() 并使用该值执行 DATEADD() 操作，

CONVERT(Datetime, DATEADD(MONTH, tb_files.file_retentiondate, MAX((SELECT tb_records.rec_record_date FROM tb_records)))) AS ExpiryDate

我试过的是这样的：

SELECT tb_files.file_pk AS 'File Number',
       tb_files.file_subject AS 'File Subject',
       CONVERT(Datetime, DATEADD(MONTH, tb_files.file_retentiondate, MAX(
                                                                           (SELECT tb_records.rec_record_date
                                                                            FROM tb_records)))) AS ExpiryDate,
       tb_compartment.comp_cab_fk AS 'Storage Number',
       tb_compartment.comp_part AS 'Compartment Number',
       tb_departments.dept_code AS 'Department',
       tb_location.locationno AS 'Location',
       tb_users.usr_fullname AS 'Created by',
       tb_files.file_datecreated AS 'Date Created'
FROM tb_files
INNER JOIN tb_fileparts ON tb_files.file_pk = tb_fileparts.fp_file_fk
INNER JOIN tb_records ON tb_fileparts.fp_pk = tb_records.rec_filepart_fk
INNER JOIN tb_users ON tb_files.file_createdby_usr_fk = tb_users.usr_pk
INNER JOIN tb_compartment ON tb_files. file_comp_fk = tb_compartment. comp_pk
INNER JOIN tb_cabinet ON tb_compartment.comp_cab_fk = tb_cabinet.cab_pk
INNER JOIN tb_location ON tb_cabinet.cab_location_fk = tb_location.location_pk
INNER JOIN tb_departments ON tb_cabinet.cab_dept_fk = tb_departments.dept_pk
WHERE (tb_files.file_active = 1)
  AND (tb_records.rec_active = 1)
GROUP BY tb_files.file_pk,
         tb_files.file_subject,
         tb_files.file_retentiondate,
         tb_compartment.comp_cab_fk,
         tb_compartment.comp_part,
         tb_departments.dept_code,
         tb_location.locationno,
         tb_users.usr_fullname,
         tb_files.file_datecreated HAVING(Convert(DateTime, DateAdd(MONTH, tb_files.file_retentiondate, MAX(tb_records.rec_record_date))) <= getdate())

我收到此错误消息：

Msg 130, Level 15, State 1, Line 2
Cannot perform an aggregate function on an expression containing an aggregate or a subquery.

你能解释一下我做错了什么吗？

Answer 1

错误消息描述性很强。 SQL 不允许您对聚合函数的参数使用子查询。简单的解决方案是将聚合移动到子查询中：

   . . .
   CONVERT(Datetime, DATEADD(MONTH, tb_files.file_retentiondate,
           (SELECT MAX(tb_records.rec_record_date)
            FROM tb_records
           )
          ) AS ExpiryDate,

Answer 2

你不能像那样用 MAX() 函数包装子查询...试试这个：

SELECT tb_files.file_pk AS 'File Number',
       tb_files.file_subject AS 'File Subject',
       CONVERT(Datetime, DATEADD(MONTH, tb_files.file_retentiondate, (SELECT MAX(tb_records.rec_record_date) FROM tb_records))) AS ExpiryDate,
       tb_compartment.comp_cab_fk AS 'Storage Number',
       tb_compartment.comp_part AS 'Compartment Number',
       tb_departments.dept_code AS 'Department',
       tb_location.locationno AS 'Location',
       tb_users.usr_fullname AS 'Created by',
       tb_files.file_datecreated AS 'Date Created'
FROM tb_files
INNER JOIN tb_fileparts ON tb_files.file_pk = tb_fileparts.fp_file_fk
INNER JOIN tb_records ON tb_fileparts.fp_pk = tb_records.rec_filepart_fk
INNER JOIN tb_users ON tb_files.file_createdby_usr_fk = tb_users.usr_pk
INNER JOIN tb_compartment ON tb_files. file_comp_fk = tb_compartment. comp_pk
INNER JOIN tb_cabinet ON tb_compartment.comp_cab_fk = tb_cabinet.cab_pk
INNER JOIN tb_location ON tb_cabinet.cab_location_fk = tb_location.location_pk
INNER JOIN tb_departments ON tb_cabinet.cab_dept_fk = tb_departments.dept_pk
WHERE (tb_files.file_active = 1)
  AND (tb_records.rec_active = 1)
GROUP BY tb_files.file_pk,
         tb_files.file_subject,
         tb_files.file_retentiondate,
         tb_compartment.comp_cab_fk,
         tb_compartment.comp_part,
         tb_departments.dept_code,
         tb_location.locationno,
         tb_users.usr_fullname,
         tb_files.file_datecreated HAVING(Convert(DateTime, DateAdd(MONTH, tb_files.file_retentiondate, MAX(tb_records.rec_record_date))) <= getdate())

Answer 3

将您的最大查询更改为..

SELECT MAX(A.rec_record_date) FROM tb_records A

按照您编写查询的方式，整个 table 的 MAX record_Date 将针对结果集中的每一行反复计算。我希望您创建一个 CTE/subquery 并重用该值...

DateAdd() 中的嵌套 SELECT 语句

Nested SELECT statement in DateAdd()

sql

tsql

sql-server

select

nested