data unpivot list ids of after group_concat - mysql

Question

Here is link to : Sqlfiddle
contents of my table
mysql> select * from tb_dts;
+----+------+------+
| Id | key1 | key2 |
+----+------+------+
| 1 | 1 | 1 |
| 2 | 1 | 1 |
| 3 | 1 | 1 |
| 4 | 2 | 1 |
| 5 | 2 | 1 |
| 6 | 2 | 1 |
| 7 | 2 | 1 |
| 8 | 1 | 2 |
| 9 | 1 | 2 |
| 10 | 1 | 2 |
| 11 | 1 | 2 |
| 12 | 1 | 2 |
| 13 | 3 | 1 |
| 14 | 3 | 1 |
| 15 | 3 | 1 |
| 16 | 3 | 1 |
| 17 | 2 | 2 |
| 18 | 2 | 2 |
| 19 | 2 | 2 |
| 20 | 2 | 3 |
| 21 | 2 | 3 |
| 22 | 2 | 3 |
| 23 | 3 | 2 |
| 24 | 3 | 2 |
| 25 | 3 | 2 |
| 26 | 3 | 2 |
+----+------+------+
26 rows in set (0.00 sec)
This is what I tried
mysql> select group_concat(id) from tb_dts group by key1,key2 limit 0,4;
+------------------+
| group_concat(id) |
+------------------+
| 1,2,3 |
| 8,9,10,11,12 |
| 4,5,6,7 |
| 17,18,19 |
+------------------+
4 rows in set (0.00 sec)
mysql> select id from tb_dts group by key1,key2 limit 0,4;
+----+
| id |
+----+
| 1 |
| 8 |
| 4 |
| 17 |
+----+
4 rows in set (0.00 sec)
This is what I expect to get as output for group by key1,key2 limit 0,4; : I want all id in one column, which falls within a limit group by key1 and key2, I don't know how to get it group_concat can't help me on this
for first 4 unique combination of key1,key2 what all id falls is my question that is using group by key1,key2 limit 0,4;
+----+
| id |
+----+
| 1 |
| 2 |
| 3 |
| 8 |
| 9 |
| 10 |
| 11 |
| 12 |
| 4 |
| 5 |
| 6 |
| 7 |
| 17 |
| 18 |
| 19 |
+----+
15 rows in set (0.00 sec)
Table Structure
DROP TABLE IF EXISTS `tb_dts`;
CREATE TABLE `tb_dts` (
`Id` int(11) NOT NULL AUTO_INCREMENT,
`key1` int(11) DEFAULT '-99',
`key2` int(11) DEFAULT '-99',
PRIMARY KEY (`Id`),
KEY `main` (`key1`,`key2`)
) ENGINE=MyISAM AUTO_INCREMENT=27 DEFAULT CHARSET=latin1;
LOCK TABLES `tb_dts` WRITE;
INSERT INTO `tb_dts` VALUES (1,1,1),(2,1,1),(3,1,1),(4,2,1),(5,2,1),(6,2,1),(7,2,1),(8,1,2),(9,1,2),(10,1,2),(11,1,2),(12,1,2),(13,3,1),(14,3,1),(15,3,1),(16,3,1),(17,2,2),(18,2,2),(19,2,2),(20,2,3),(21,2,3),(22,2,3),(23,3,2),(24,3,2),(25,3,2),(26,3,2);
UNLOCK TABLES;

Answer 1

Use the Separator as below
select group_concat(id SEPARATOR '\n') from tb_dts group by key1,key2

Answer 2

If order doesn't matter then try :
See Output here : SQL Fiddle
select id
from tb_dts
where (key1,key2) in (
select key1,key2
from (
select distinct key1,key2 from tb_dts limit 0,4
) as sub
);

Answer 3

There is a way to solve question.
First you have to create a Table like
CREATE TABLE `Tmp` (
`Id` int(11)
);
And then, after you run the code
select #TmpStr = group_concat(id) from tb_dts group by key1,key2 limit 0,1;
--#TmpStr = "1,2,3"
Write a funtion to Split #TmpStr by "," and Insert into Tmp separately.
And keep doing same thing for
select #TmpStr = group_concat(id) from tb_dts group by key1,key2 limit 1,1;
select #TmpStr = group_concat(id) from tb_dts group by key1,key2 limit 2,1;
select #TmpStr = group_concat(id) from tb_dts group by key1,key2 limit 3,1;
it will show the result like you want.