2017.7.14 使用case when和group by将多条数据合并成一行，并且根据某些列的合并值做条件判断来生成最终值

1.效果演示

（1）不做处理

（2）合并多列，并对后四列的值做并集处理

2.SQL语句

（1）不做处理

1 SELECT
2     C .fd_tenantid AS fdTenantId,
3     C .fd_resid AS fdResid,
4     C .fd_res_name AS fdResName,
5     C .fd_service AS fdService,
6     b.fd_get AS fdGET,
7     b.fd_post AS fdPOST,
8     b.fd_put AS fdPUT,
9     b.fd_delete AS fdDELETE
10 FROM
11     t_usergroup AS A
12 INNER JOIN t_permission AS b ON A .fd_groupid = b.fd_groupid
13 INNER JOIN t_resource AS C ON b.fd_resid = C .fd_resid
14 INNER JOIN t_tenant AS d ON A .fd_tenantid = d.fd_tenantid
15 WHERE
16     d.fd_tenant_name = 'root'
17   and a.fd_groupid  in (10026,10029)
18
19 ORDER BY c.fd_res_name

（2）合并多列，并对后四列的值做并集处理

1 SELECT
2     C .fd_tenantid AS fdTenantId,
3     C .fd_resid AS fdResid,
4     C .fd_res_name AS fdResName,
5     C .fd_service AS fdService,
6      (CASE WHEN SUM(b.fd_get) >=1 THEN 1 ELSE 0 END) AS fdGET,
 7      (CASE WHEN SUM(b.fd_post) >=1 THEN 1 ELSE 0 END) AS fdPOST,
8      (CASE WHEN SUM(b.fd_put) >=1 THEN 1 ELSE 0 END) AS fdPUT,
9      (CASE WHEN SUM(b.fd_delete) >=1 THEN 1 ELSE 0 END) AS fdDELETE
10 FROM
11     t_usergroup AS A
12 INNER JOIN t_permission AS b ON A .fd_groupid = b.fd_groupid
13 INNER JOIN t_resource AS C ON b.fd_resid = C .fd_resid
14 INNER JOIN t_tenant AS d ON A .fd_tenantid = d.fd_tenantid
15 WHERE
16     d.fd_tenant_name = 'root'
17   and a.fd_groupid  in (10026,10029)
18
19 GROUP BY 
20    d.fd_tenantid,c.fd_resid,c.fd_service
21
22 ORDER BY c.fd_res_name