有时候,只是想查看某个table中有多少个条记录,并不是想看所有的结果。
这个时候
select * from [tablename]
就显得有点杀鸡用牛刀的感觉了。
我们可以用
select count(*) as total_record from [tablename];
例如:
select count(** as total_record from students;
+————–+
| total_record |
+————–+
| 14 |
+————–+
1 row in set (0.00 sec)
就会显示有14条记录。
我们还可以加上条件:
select count(*) as total_record from [tablename] where [condition];
例如:
select count(** as total_record from students where grade=’2′;
完。
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