mysql:
select count(*) from main_index;
但是这个在这里却报语法错误。
第一种方法:
查文档得:
Aggregate functions (AVG(), MIN(), MAX(), SUM()) in column list clause are supported. Arguments to aggregate functions can be either plain attributes or arbitrary expressions. COUNT(*) is implicitly supported as using GROUP BY will add @count column to result set. Explicit support might be added in the future. COUNT(DISTINCT attr) is supported. Currently there can be at most one COUNT(DISTINCT) per query and an argument needs to be an attribute. Both current restrictions on COUNT(DISTINCT) might be lifted in the future.
也就是说只有在group by的时候才能用count(*),如:
复制代码 代码如下:
select 1 as dummy,count(*) c from main_index group by dummy;
+------+--------+-------+--------+
| id | weight | dummy | @count |
+------+--------+-------+--------+
| 1001 | 1 | 1 | 15659 |
+------+--------+-------+--------+
第二种方法
复制代码 代码如下:
select * from main_index limit 0;
show meta;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| total | 67 |
| total_found | 67 |
| time | 0.001 |
| keyword[0] | ha |
| docs[0] | 67 |
| hits[0] | 115 |
+---------------+-------+
也就是说用show meta来得到这个total_found,这个就是总记录数。
下面我们来说一下show meta:
SHOW META shows additional meta-information about the latest query such as query time and keyword statistics:
也就是说它显示的是最近一次查询附加的一些信息,比如查询时间、关键字统计、总记录等。
复制代码 代码如下:
mysql> SELECT * FROM test1 WHERE MATCH('test|one|two');
+------+--------+----------+------------+
| id | weight | group_id | date_added |
+------+--------+----------+------------+
| 1 | 3563 | 456 | 1231721236 |
| 2 | 2563 | 123 | 1231721236 |
| 4 | 1480 | 2 | 1231721236 |
+------+--------+----------+------------+
3 rows in set (0.01 sec)
mysql> SHOW META;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| total | 3 |
| total_found | 3 |
| time | 0.005 |
| keyword[0] | test |
| docs[0] | 3 |
| hits[0] | 5 |
| keyword[1] | one |
| docs[1] | 1 |
| hits[1] | 2 |
| keyword[2] | two |
| docs[2] | 1 |
| hits[2] | 2 |
+---------------+-------+
12 rows in set (0.00 sec)
在PHP中如何调用?
复制代码 代码如下:
<?php
//获取总记录个数
private function getTotalFound($conn) {
$sql = "show meta";
$total_result = @mysql_query ( $sql,$conn );
$totals = array ();
while ( ($row = mysql_fetch_assoc ( $total_result )) !== false ) {
$totals [$row ['Variable_name']] = $row ['Value'];
}
return $totals;
}
?>
注意:如果代码中用了多个数据库连接的话,这个相应的conn必须传进来,否则是取不到结果的。
更新日志
- 单依纯《纯情歌》2024最新 开盘母带1:1直刻[547M]
- 永劫无间手游沈妙怎么样 技能奥义介绍
- 三角洲行动穿透机制介绍 穿透等级穿透效果一览
- 吟游战记巨刃特蕾值得培养吗 角色技能属性详解
- 逆水寒手游创意工坊玩法介绍 逆水寒创意工坊怎么玩
- 逆水寒手游雀隐重楼玩法介绍 逆水寒手游雀隐重楼是什么
- 逆水寒手游神器系统玩法攻略 逆水寒手游神器系统怎么玩
- PS5首席架构师提交新专利:PS5有望原生运行PS3游戏?
- 数据显示:《地狱潜者2》在PC平台已失去90%的玩家
- 质疑和守望先锋太像?《星鸣特攻》开发商:我们与众不同
- 【休闲沙发】VA-2024-CalmReflections:ChilloutYourMind(FLAC)
- 【迷幻沙发】Koan(公案)-2024-TheQueenofSpades(SideA)(FLAC)
- 群星2006-银河映像1996-20052CD[香港首版][WAV+CUE]
- 外媒盘点游戏里十大最可怕外星生物:第一名是老熟人
- 阿拉贡演员谈参演《咕噜》新电影:要视情况而定