是否有一种方法可以获得MySQL数据库中所有表的行计数,而无需在每个表上运行SELECT count() ?
当前回答
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
其他回答
这是我如何使用PHP计算表和所有记录:
$dtb = mysql_query("SHOW TABLES") or die (mysql_error());
$jmltbl = 0;
$jml_record = 0;
$jml_record = 0;
while ($row = mysql_fetch_array($dtb)) {
$sql1 = mysql_query("SELECT * FROM " . $row[0]);
$jml_record = mysql_num_rows($sql1);
echo "Table: " . $row[0] . ": " . $jml_record record . "<br>";
$jmltbl++;
$jml_record += $jml_record;
}
echo "--------------------------------<br>$jmltbl Tables, $jml_record > records.";
海报想要行计数,但没有指定哪个表引擎。对于InnoDB,我只知道一种方法,那就是计数。
我是这样摘土豆的:
# Put this function in your bash and call with:
# rowpicker DBUSER DBPASS DBNAME [TABLEPATTERN]
function rowpicker() {
UN=$1
PW=$2
DB=$3
if [ ! -z "$4" ]; then
PAT="LIKE '$4'"
tot=-2
else
PAT=""
tot=-1
fi
for t in `mysql -u "$UN" -p"$PW" "$DB" -e "SHOW TABLES $PAT"`;do
if [ $tot -lt 0 ]; then
echo "Skipping $t";
let "tot += 1";
else
c=`mysql -u "$UN" -p"$PW" "$DB" -e "SELECT count(*) FROM $t"`;
c=`echo $c | cut -d " " -f 2`;
echo "$t: $c";
let "tot += c";
fi;
done;
echo "total rows: $tot"
}
我对此没有任何断言,只是说这是一种非常丑陋但有效的方法,可以获得数据库中每个表中存在多少行,而不需要使用表引擎,也不需要拥有安装存储过程的权限,也不需要安装ruby或php。是的,生锈了。是的,这很重要。Count(*)是准确的。
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.
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)
如果你知道表的数量和它们的名称,并且假设它们每个都有主键,你可以使用交叉连接结合COUNT(distinct [column])来获得来自每个表的行:
SELECT
COUNT(distinct t1.id) +
COUNT(distinct t2.id) +
COUNT(distinct t3.id) AS totalRows
FROM firstTable t1, secondTable t2, thirdTable t3;
下面是一个SQL Fiddle的例子。
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