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.";

如果你使用数据库information_schema，你可以使用下面的mysql代码(where部分使查询不显示行为空值的表):

SELECT TABLE_NAME, TABLE_ROWS
FROM `TABLES`
WHERE `TABLE_ROWS` >=0

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。

大多数其他答案建议使用INFORMATION_SCHEMA。但是在MySQL 8中它已经不存在了。行数已移动到INFORMATION_SCHEMA.INNODB_TABLESTATS。

你可以用以下方法查询:

SELECT *
FROM information_schema.INNODB_TABLESTATS
WHERE NAME LIKE "YOUR_DB_NAME/%"
ORDER BY NUM_ROWS DESC

请注意，这仍然是一个近似值，像以前一样，不是一个确切的数字。

这个存储过程列出表，统计记录，并在最后生成记录的总数。

添加此过程后运行:

CALL `COUNT_ALL_RECORDS_BY_TABLE` ();

-

过程:

DELIMITER $$

CREATE DEFINER=`root`@`127.0.0.1` PROCEDURE `COUNT_ALL_RECORDS_BY_TABLE`()
BEGIN
DECLARE done INT DEFAULT 0;
DECLARE TNAME CHAR(255);

DECLARE table_names CURSOR for 
    SELECT table_name FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = DATABASE();

DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1;

OPEN table_names;   

DROP TABLE IF EXISTS TCOUNTS;
CREATE TEMPORARY TABLE TCOUNTS 
  (
    TABLE_NAME CHAR(255),
    RECORD_COUNT INT
  ) ENGINE = MEMORY; 


WHILE done = 0 DO

  FETCH NEXT FROM table_names INTO TNAME;

   IF done = 0 THEN
    SET @SQL_TXT = CONCAT("INSERT INTO TCOUNTS(SELECT '" , TNAME  , "' AS TABLE_NAME, COUNT(*) AS RECORD_COUNT FROM ", TNAME, ")");

    PREPARE stmt_name FROM @SQL_TXT;
    EXECUTE stmt_name;
    DEALLOCATE PREPARE stmt_name;  
  END IF;

END WHILE;

CLOSE table_names;

SELECT * FROM TCOUNTS;

SELECT SUM(RECORD_COUNT) AS TOTAL_DATABASE_RECORD_CT FROM TCOUNTS;

END

SELECT SUM(TABLE_ROWS) 
     FROM INFORMATION_SCHEMA.TABLES 
     WHERE TABLE_SCHEMA = '{your_db}';

从文档中注意到:对于InnoDB表，行数只是用于SQL优化的粗略估计。您需要使用COUNT(*)来获得精确的计数(成本更高)。