MySQL Query grouping

Data sheet:
ID N T
1 a 1
2 B 1
3 C 2
4 D 2
5 E 3
1 F 3

The data I want to extract is grouped by T:

  [      1=>[          0=>[              'id'=>1,              'n'=>'a',              't'=>1          ],          1=>[              'id'=>2,              'n'=>'a',              't'=>1          ]      ]   ]

After I use GROUP by, each category will only get one data, not all

Reply content:

Data sheet:
ID N T
1 a 1
2 B 1
3 C 2
4 D 2
5 E 3
1 F 3

The data I want to extract is grouped by T:

  [      1=>[          0=>[              'id'=>1,              'n'=>'a',              't'=>1          ],          1=>[              'id'=>2,              'n'=>'a',              't'=>1          ]      ]   ]

After I use GROUP by, each category will only get one data, not all

Group BY is the only one that returns the first data. If you want to return field information in a group, you can use the following SQL

select id,user_id,GROUP_CONCAT(`order_no`) ,count(`id`) from `table` group by `user_id`

Group_concat This can be queried for all values that need to be listed, and placed in a field, separated by commas.

You can use order by and then traverse the grouping in PHP
The other way is Group_concat + concat, like
Select T, concat (' ['), Group_concat (Concat (' {id: ', ', ' N: ', ', ' id n } ')), '] ') as details from table GROUP byt
This should be to get a similar
1 [{id:1,n: "a"},{id:2,n: "A"}] this kind of record, you json_decode.

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