MySQL sorts according to the specified order of the specified fields

SELECT `id`,`name` FROM `user` WHERE id IN(1,3,5,6) ORDER BY INSTR('6,3,5,1', 'id')

  I found it on the Internet before , But then I forgot , Look for it again, and you won't find it , Most of the Internet is case  when But what if there is a large amount of data ？ I didn't find it, so I searched the code for a long time , Better a good memory than a bad pen , So I wrote this .