比较PHP中的sql varchar

I have the Database:

(NumbersAndLetter is VARCHAR, utf8_general_ci)

ID | NumbersAndLetter | switch
1 | Uf3zb37FvV| 1
2 | F9bFgsb7F| 1

I try to change the database entry with PHP through the NumbersAndLetter, but it will not compare

$Something = 'Uf3zb37FvV';

$entry = $intoDB->GetRow("INSERT INTO database (switch) VALUES ('2') WHERE NumbersAndLetter=".$Something);

It can not compare $Something with the NumbersAndLetter of the Database, even if it is the same. How can I get this work to compare $Something with NumbersAndLetter correctly?