SQL is not the same thing as SEQUEL. If you’re a grumpy old DBA, stuck in your ways, who actually used SEQUEL back in the 1970s, that’s fine. For all the new kids just getting into SQL, it’s pronounced es-que-el, not sequel. When you call it sequel, you sound like just as much of an idiot as someone who says lynuks. It’s annoying.
The “SQL” pronunciation is actually defined in the original 1986 specification for SQL and confirmed by common DBMS such as MySQL.