PHP，从sql数据库显示泰国字符

Inside a sql data database I have some filed with Thai character. When I'm querying the database to display these name, some character are displaying, but some are not, question marque instead of the character.

Any idea what should I do to display the whole name?

So far I added this in my html:

<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=windows-874">
<META HTTP-EQUIV="Content-language" CONTENT="th">