PHP MySQL UPDATE statement number normal insertion, letter kanji No

Digital phpupdate Insertion

The combination of PHP and MySQL, for the operation of the number is completely correct, the database table is the property of varchar, the database is also set UTF8, but the problem should not be here, not only Chinese characters do not, the English alphabet is not, as long as 6 columns in a row of non-digital words, the update will not fail, But all columns become empty, and the UPDATE statement is as follows:
$query = "Update user set Firstname= '". $_get[firstname]. "', Lastname= '". $_get[lastname]. "', age= '". $_get[age]. "', Hometown= ' ". $_get[hometown]." ', job= ' ". $_get[job]." ' where Id=$_get[id] ";
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