为什么这个MySQL查询只返回1个结果？

Question

Is the syntax right?

SELECT * 
  FROM productOptions 
 WHERE productOptionsID IN ('1,2,3,4')

Have I used IN properly, or should the comma separated values be different?

This is followed by the following code:

$optionsresultsql= mysql_query($optionsquerysql) or die(mysql_error());

while($optionssql = mysql_fetch_array($optionsresultsql)) {
  $optionNamesID = $optionssql["optionNamesID"];
  echo $optionNamesID;
}   

Only one result is shown, even though there are 4 matches in the DB.

Answer 1

处理INT查找时删除单一滴答。

"SELECT * FROM productOptions WHERE productOptionsID IN (1,2,3,4)"

Answer 2

'1,2,3,4' is a string, which is being converted to an int. MySQL converts strings to ints by reading up until the 1st non-number character, in your case, the , .

So,

IN ('1,2,3,4') = IN (CAST('1,2,3,4' AS INT)) = IN (1)

The query should just be:

productOptionsID IN (1,2,3,4)