像许多其他人一样，我很难用InnoDB在INFORMATION_SCHEMA表上获得准确的值，并且能够通过count()进行查询将无限受益，并且希望在一次查询中完成它。

首先，确保启用大规模group_concats:

SET SESSION group_concat_max_len = 1000000;

然后运行此查询以获得将为数据库运行的结果查询。

SELECT CONCAT('SELECT ', GROUP_CONCAT(table1.count SEPARATOR ',\n')) FROM (
    SELECT concat('(SELECT count(id) AS \'',table_name,' Count\' ','FROM ',table_name,') AS ',table_name,'_Count') AS 'count'
    FROM information_schema.tables 
    WHERE table_schema = '**YOUR_DATABASE_HERE**'
) AS table1

这将生成诸如…

SELECT (SELECT count(id) AS 'table1 Count' FROM table1) AS table1_Count,
   (SELECT count(id) AS 'table2 Count' FROM table2) AS table2_Count,
   (SELECT count(id) AS 'table3 Count' FROM table3) AS table3_Count;

这反过来又产生了以下结果:

*************************** 1. row ***************************
table1_Count: 1
table2_Count: 1
table3_Count: 0

我不知道为什么这么难，但这就是生活。 下面是执行实际计数的bash脚本。只需将其保存为(例如count_rows.sh)，使其可执行(例如chmod 755 count_rows.sh)，并运行它(例如。/count_rows.sh)

#!/bin/bash

readarray -t TABLES < <(mysql --skip-column-names -u myuser -pmypassword mydbname -e "show tables")

# now we have an array like:
# TABLES='([0]="customer" [1]="order" [2]="product")'
# You can print out the array with:
#declare -p TABLES


for i in "${TABLES[@]}"
do
    #echo $i
    COUNT=$(mysql --skip-column-names -u username -pmypassword mydbname -e  "select count(*) from $i")
    echo $i : $COUNT
done

像@Venkatramanan和其他人一样，我找到了INFORMATION_SCHEMA。TABLES不可靠(使用InnoDB, MySQL 5.1.44)，每次运行时给出不同的行数，即使是在静态表上。这里有一种生成大型SQL语句的相对hack(但是灵活/适应性强)的方法，您可以将其粘贴到新的查询中，而不需要安装Ruby宝石之类的东西。

SELECT CONCAT(
    'SELECT "', 
    table_name, 
    '" AS table_name, COUNT(*) AS exact_row_count FROM `', 
    table_schema,
    '`.`',
    table_name, 
    '` UNION '
) 
FROM INFORMATION_SCHEMA.TABLES 
WHERE table_schema = '**my_schema**';

它产生如下输出:

SELECT "func" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.func UNION                         
SELECT "general_log" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.general_log UNION           
SELECT "help_category" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.help_category UNION       
SELECT "help_keyword" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.help_keyword UNION         
SELECT "help_relation" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.help_relation UNION       
SELECT "help_topic" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.help_topic UNION             
SELECT "host" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.host UNION                         
SELECT "ndb_binlog_index" AS table_name, COUNT(*) AS exact_row_count FROM my_schema.ndb_binlog_index UNION 

复制粘贴，除了最后一个UNION，可以得到漂亮的输出，

+------------------+-----------------+
| table_name       | exact_row_count |
+------------------+-----------------+
| func             |               0 |
| general_log      |               0 |
| help_category    |              37 |
| help_keyword     |             450 |
| help_relation    |             990 |
| help_topic       |             504 |
| host             |               0 |
| ndb_binlog_index |               0 |
+------------------+-----------------+
8 rows in set (0.01 sec)

还有一个选择:对于非InnoDB，它使用information_schema中的数据。TABLES(因为它更快)，对于InnoDB -选择count(*)来获得准确的计数。它还会忽略视图。

SET @table_schema = DATABASE();
-- or SET @table_schema = 'my_db_name';

SET GROUP_CONCAT_MAX_LEN=131072;
SET @selects = NULL;

SELECT GROUP_CONCAT(
        'SELECT "', table_name,'" as TABLE_NAME, COUNT(*) as TABLE_ROWS FROM `', table_name, '`'
        SEPARATOR '\nUNION\n') INTO @selects
  FROM information_schema.TABLES
  WHERE TABLE_SCHEMA = @table_schema
        AND ENGINE = 'InnoDB'
        AND TABLE_TYPE = "BASE TABLE";

SELECT CONCAT_WS('\nUNION\n',
  CONCAT('SELECT TABLE_NAME, TABLE_ROWS FROM information_schema.TABLES WHERE TABLE_SCHEMA = ? AND ENGINE <> "InnoDB" AND TABLE_TYPE = "BASE TABLE"'),
  @selects) INTO @selects;

PREPARE stmt FROM @selects;
EXECUTE stmt USING @table_schema;
DEALLOCATE PREPARE stmt;

如果你的数据库有很多大的InnoDB表，计算所有行会花费更多的时间。

如果需要精确的数字，请使用下面的ruby脚本。你需要Ruby和RubyGems。

安装以下Gems:

$> gem install dbi
$> gem install dbd-mysql

文件:count_table_records.rb

require 'rubygems'
require 'dbi'

db_handler = DBI.connect('DBI:Mysql:database_name:localhost', 'username', 'password')

# Collect all Tables
sql_1 = db_handler.prepare('SHOW tables;')
sql_1.execute
tables = sql_1.map { |row| row[0]}
sql_1.finish

tables.each do |table_name|
  sql_2 = db_handler.prepare("SELECT count(*) FROM #{table_name};")
  sql_2.execute
  sql_2.each do |row|
    puts "Table #{table_name} has #{row[0]} rows."
  end
  sql_2.finish
end

db_handler.disconnect

回到命令行:

$> ruby count_table_records.rb

输出:

Table users has 7328974 rows.

下面的查询生成一个(另一个)查询，该查询将从information_schema.tables中列出的每个模式中获取每个表的count(*)值。这里显示的查询的整个结果——所有行放在一起——包含一个以分号结尾的有效SQL语句——没有悬空的“联合”。在下面的查询中使用联合来避免悬空联合。

select concat('select "', table_schema, '.', table_name, '" as `schema.table`,
                          count(*)
                 from ', table_schema, '.', table_name, ' union ') as 'Query Row'
  from information_schema.tables
 union
 select '(select null, null limit 0);';