MySQL将两个记录合并为一个

Question

I have status table with

id (primary key )
case id 
read status
delivered status

now I can have multiple records for same case id with different values

Here I have case ID (111) with two rows

ID  case_id     read_status     delivered_status
1   111         1                0
2   111         0                1

How can I run query so it gives one row for above case with read status and delivery status to 1 ?

SqlFiddle

http://sqlfiddle.com/#!9/9d977e/1

Answer 1

read status and delivery status to 1

Do you mean the max value ? If so, here is the fiddle.

Fiddle

The query :

select 
  `case_id`,
  max(`read_status`),
  max(`delivered_status`)
from status
group by `case_id`

Answer 2

您可以按case_id分组，并简单地获得分组中列的最大值

select id, case_id ,max(read_status) as read_status , max(delivered_status) as delivered_status  from status group by case_id