What is the equivalent in T-SQL SQL Server to the "&" symbol, VFP macro substitution?.

E.g., I need to do this VFP's example in T-SQL.

lcCond = " name like '%John%' "
SELECT * FROM customers where &lccond

or

lcCond = " invoicenumber > 1056 "
SELECT * FROM invoices where &lccond

How it would be in T-SQL ?

T.I.A.