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mysql found_row()使用详解_MySQL

May 27, 2016 pm 01:45 PM

mysql found_row()用于获取Select得到的行数,比如有段sql需要取出一张表的前10行,同时又需要取出符合条件的总数。 本文章向大家介绍mysql found_row的用法,感兴趣的可以参考一下。

mysql 4.1中新增了FOUND_ROWS()函数,这个函数的说明是这样的:


代码如下:

For a SELECT with a LIMIT clause, the number of rows that would be returned were there no LIMIT clause
A SELECT statement may include a LIMIT clause to restrict the number of rows the server returns to the client.
 In some cases, it is desirable to know how many rows the statement would have returned without the LIMIT, 
 but without running the statement again. To obtain this row count, include a SQL_CALC_FOUND_ROWS option in the
  SELECT statement, and then invoke FOUND_ROWS() afterward:
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比如说有段sql需要取出一张表的前10行,同时又需要取出符合条件的总数。这在某些分页操作中很常见


SELECT SQL_CALC_FOUND_ROWS * FROM tbl_name
WHERE id > 100 LIMIT 10;
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在上一查询之后,你只需要用FOUND_ROWS()就能获得查询总数,这个数目是抛掉了LIMIT之后的结果数:


SELECT FOUND_ROWS();
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其中第一个sql里面的SQL_CALC_FOUND_ROWS不可省略,它表示需要取得结果数,也是后面使用FOUND_ROWS()函数的铺垫。

记一次使用中遇到的问题的解决方法

写MySQL分页使用了发现FOUND_ROWS总是返回1,实际记录绝不止1条。SQL语句如下:


select sql_calc_found_rows * from actionlist where A_ID > 0 limit 10;
select FOUND_ROWS();
Copy after login


网上查找中文资料,没有解决。英文资料找到问题原因

使用MySQL Workbech出现了上述问题。使用MySQL Command Line Client执行同样SQL语句返回值OK!

要是遇到同样问题,试试!

以上就是mysql found_row()使用详解_MySQL的内容,更多相关内容请关注PHP中文网(www.php.cn)!


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