前言

对于开发或者运维人员来说，Mysql数据库每张表的数量肯定是要了解下，有助于我们清理无用数据或者了解哪张表比较占用空间。

另外多次统计表的行数，还能发现Mysql表的增量情况，能够预测表未来会有多大的量。

废话不多说，直接带大家写一个简单的Shell小脚本

循环获取数据库名

直接上Shell代码，show databases获取所有的库名。结果有一个我们不想要的，就是Database，这个grep -v掉，轻松获取所有数据库

[root@shijiangeit ~]# mysql -h 127.0.0.1 -uxxx -pxxx -e "show databases;" 2>/dev/null
+--------------------+
| Database      |
+--------------------+
| information_schema |
| mysql       |
| performance_schema |
| shijiange     |
| test        |
| wordpress     |
+--------------------+

[root@shijiangeit ~]# mysql -h 127.0.0.1 -uxxx -pxxx -e "show databases;" 2>/dev/null |grep -v Database
information_schema
mysql
performance_schema
shijiange
test
wordpress

循环获取所有表

有了库信息，获取所有表就简单了，直接上Shell代码。show tables获取所有表名，其中Tables_in不需要，grep -v掉。

[root@shijiangeit ~]# for onedb in $(mysql -h 127.0.0.1 -uxxx -pxxx -e "show databases;" 2>/dev/null |grep -v Database);do
>  echo $onedb
>  mysql -h 127.0.0.1 -uxxx -pxxx $onedb -e "show tables" 2>/dev/null
> done
information_schema
+---------------------------------------+
| Tables_in_information_schema     |
+---------------------------------------+
| CHARACTER_SETS            |
| COLLATIONS              |
| COLLATION_CHARACTER_SET_APPLICABILITY |
| COLUMNS                |
| COLUMN_PRIVILEGES           |
| ENGINES                |
| EVENTS                |
| FILES                 |
| GLOBAL_STATUS             |
| GLOBAL_VARIABLES           |
| KEY_COLUMN_USAGE           |

循环统计每张表的行数

取出库名加表名，一个select count(1)统计表的行数，循环统计，直接上Shell代码。

[root@shijiangeit ~]# for onedb in $(mysql -h 127.0.0.1 -uxxx -pxxx -e "show databases;" 2>/dev/null |grep -v Database);do
>  for onetab in $(mysql -h 127.0.0.1 -uxxx -pxxx $onedb -e "show tables" 2>/dev/null |grep -v 'Tables_in_');do
>   onetablength=$(mysql -h 127.0.0.1 -uxxx -pxxx $onedb -e "select count(1) from $onetab" 2>/dev/null |grep -v 'count')
>   echo -e "$onedb.$onetab\t$onetablength"
>  done
> done
information_schema.CHARACTER_SETS  40
information_schema.COLLATIONS  219
information_schema.COLLATION_CHARACTER_SET_APPLICABILITY  219
information_schema.COLUMNS 1789
information_schema.COLUMN_PRIVILEGES  0
shijiange.logincount  4
shijiange.member  0
shijiange.user 2097153
test.detect_servers 0
wordpress.wp_commentmeta  0
wordpress.wp_comments  0
wordpress.wp_links 0
wordpress.wp_options  156

变量化，脚本直接用

需要统计哪个Mysql，前面三个变量一改，立马就能统计所有表的大小了。

mysqlhost=127.0.0.1
mysqluser=xxx
mysqlpassword=xxx

for onedb in $(mysql -h $mysqlhost -u$mysqluser -p$mysqlpassword -e "show databases;" 2>/dev/null |grep -v Database);do
 for onetab in $(mysql -h $mysqlhost -u$mysqluser -p$mysqlpassword $onedb -e "show tables" 2>/dev/null |grep -v 'Tables_in_');do
  onetablength=$(mysql -h $mysqlhost -u$mysqluser -p$mysqlpassword $onedb -e "select count(1) from $onetab" 2>/dev/null |grep -v 'count')
  echo -e "$onedb.$onetab\t$onetablength"
 done
done