Compare a value in a variable in the script

[#1]

I have a variable VX , what is the syntax I have to use to compare in SQL script one field with the value of this variable?

I put here the example I have

Load

Sales_account

From sales  where sales_account =  variable , I want to know what is exactly the syntax for this comparison.

Thanks,

[#2]

From sales  where sales_account =$(VX)