HiSEN

sql行转列,列转行

有时候需要行转列或者列转行

在Oracle 11g中,Oracle 又增加了2个查询:pivot(行转列) 和unpivot(列转行)

下面是在mysql中的操作:

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mysql> select * from test;
+------+------+--------+
| id | age | weigth |
+------+------+--------+
| 1 | 1 | 3 |
| 1 | 2 | 2 |
| 1 | 3 | 1 |
| 2 | 5 | 6 |
+------+------+--------+
4 rows in set (0.00 sec)
#根据ID分组
mysql> select group_concat(age) from test group by id;
+-------------------+
| group_concat(age) |
+-------------------+
| 1,2,3 |
| 5 |
+-------------------+
2 rows in set (0.01 sec)
#不分组
mysql> select group_concat(age) from test;
+-------------------+
| group_concat(age) |
+-------------------+
| 1,2,3,5 |
+-------------------+
1 row in set (0.00 sec)