数一数- PHP MYSQL

Question

我的table如下：

 guid version

 A1   lol
 A2   roflmao
 A1   lol
 A1   lol
 A2   lol
 A3   roflmao
 A3   roflmao
 A3   roflmao
 A3   roflmao 
 A3   roflmao
 A3   roflmao
 A4   roflmao
 A4   roflmao
 A5   lol   
 A5   lol

我想数一数 roflmao 出现的总次数少于 3 次（每个 GUID）。

到目前为止，我有以下内容，但没有输出任何内容：

$sql="select guid,version, count(*) as `count` 
from mytable WHERE version = 'roflmao' group by guid having `count` < 3'";

if ($result=mysqli_query($con,$sql))
{

 // Return the number of rows in result set

 $rowcount=mysqli_num_rows($result);
 printf($rowcount);

 // Free result set

 mysqli_free_result($result);
 }

Answer 1

试试这个：

SELECT COUNT(*) FROM (
    SELECT guid
    FROM YourTable
    WHERE version = 'roflmao'
    GROUP BY guid
    HAVING COUNT(*) <3) t

先select所有'roflmao'出现次数少3次的guid，再统计

数一数- PHP MYSQL

Count of a count- PHP MYSQL

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frequency

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