bitsCN.com 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：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。
MySQL（Linux）
MySQL 9.6.0是面向Linux平台的2026年创新版本，核心架构迎来重大革新。其将外键约束与级联操作从InnoDB引擎层上移至SQL层，确保所有数据变更均被完整记录至Binlog，彻底解决了CDC（变更数据捕获）与主从复制中的数据不一致难题。此外，该版本引入container_aware启动选项以原生适配容器环境，并对审计日志进行了组件化重构，为追求极致数据一致性与云原生体验的开发者提供了全新选择。
下载下面我们来说一下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。
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？
php
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。
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