concat列名取决于值

Question

我需要根据行值连接列名。以下是我的表格格式： -

表名= tbl_occupancy

所以从这张表中，如果它们的值 1 ，我需要在列下方连接： -

1. working_people
2. owner_occupied
3. 学生
4. dss_referrals
5. local_authority

输出将采用以下格式： -

Working People/Owner Occupied/Students/Dss Referrals/Local Authority 
when all of these columns value are one.

假设work_people＆amp; dss_referrals = 1然后我的输出将在下面： -

Working People/Dss Referrals

尝试一天。到目前为止还没有找到任何解

我需要在上面提到的单行中输出此输出。因为此查询将在报表模块中用作子查询。此输出将在xls工作表中显示为一列。

任何帮助PLZ。

Answer 1

您可以在CASE功能

中使用CONCAT()

SELECT
DISTINCT risk_reference, 
CONCAT(
CASE WHEN `working_people` = 1 THEN 'Working People /' ELSE '' END ,
CASE WHEN `owner_occupied` = 1 THEN 'Owner Occupied /' ELSE '' END ,
CASE WHEN `students` = 1 THEN 'Students /' ELSE '' END ,
CASE WHEN `dss_referrals` = 1 THEN 'Dss Referrals/' ELSE '' END ,
CASE WHEN `local_authority` = 1 THEN 'Local Authority' ELSE '' END 
) `concat_columns`
FROM 
`table`

修改 你可以使用DISTINCT来获得截然不同的结果，但是在你的表格中你有多行，所以虽然你可以使用GROUP BY risk_reference，但是它会有多个结果，但如果没有聚合函数则不能使用

Answer 2

我在下面的查询中使用我的解决方案： -

select group_concat("/",col.column_name) as hazards from information_schema.columns 
  as col inner join db_name.`tbl_occupancy` as oc  on col.table_schema="db_name" 
  and col.table_name = "tbl_occupancy" and col.column_name in (
           if(oc.working_people=1,"working_people",""),
           if(oc.owner_occupied=1,"owner_occupied",""),
           if(oc.students=1,"students",""),
           if(oc.dss_referrals=1,"dss_referrals",""),
           if(oc.local_authority=1,"local_authority","")
    );

Answer 3

您可以尝试：

SELECT CONCAT_WS("/",
IF(working_people=1,"working_people",""),
IF(owner_occupied=1,"owner_occupied"),
IF(students=1,"students",""),
IF(dss_referrals=1,"dss_referrals",""),
IF(local_authority=1,"local_authority","")) AS result
FROM tbl_occupancy;

Answer 4

您可以使用

  

“的concat-WS”

。它不会跳过空字符串。但是，它会在分隔符和参数之后跳过任何NULL值。

      `mysql> SELECT CONCAT_WS(',','Test',NULL,'1');
              output -> 'Test,1'`