MySQL Fixed-Length and Variable-Length Columns

MySQL

I'm trying to generate a little more performance from a particular table full of hundreds of thousands of rows. There are a few VARCHAR fields that I'm converting to CHAR.

I'm aware that I won't get the speed benefit of switching to fixed length CHAR fields if any variable length rows exist in my table. However, when I search for a list of all fixed length–or variable length–field types for MySQL, I come up short. My table contains a few DECIMAL and DATETIME fields. I'm somewhat sure the latter is fixed, but the former? Not sure.

Does anyone have a definitive list?

Best Answer

See from the official MySQL documentation: section Data Type Storage Requirements has it all.