MySQL 查询在单个查询中对多个列进行排序
mysqlmysqli database
要对多个列进行排序，请使用 ORDER BY GREATEST()。让我们首先创建一个 −
mysql> create table DemoTable1395 -> ( -> Value1 int, -> Value2 int, -> Value3 int -> ); Query OK, 0 rows affected (0.79 sec)
使用 insert 在表中插入一些记录 −
mysql> insert into DemoTable1395 values(40,50,60); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1395 values(90,56,80); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1395 values(10,20,30); Query OK, 1 row affected (0.11 sec)
使用 select 语句显示表中的所有记录 −
mysql> select * from DemoTable1395;
这将产生以下输出 −
+--------+--------+--------+ | Value1 | Value2 | Value3 | +--------+--------+--------+ | 40 | 50 | 60 | | 90 | 56 | 80 | | 10 | 20 | 30 | +--------+--------+--------+ 3 rows in set (0.00 sec)
这是对多列进行排序的查询 −
mysql> select * from DemoTable1395 -> order by greatest(Value1,Value2,Value3);
这将产生以下输出 −
+--------+--------+--------+ | Value1 | Value2 | Value3 | +--------+--------+--------+ | 10 | 20 | 30 | | 40 | 50 | 60 | | 90 | 56 | 80 | +--------+--------+--------+ 3 rows in set (0.00 sec)
