Hi,
good job you're doing with HeidiSQL. It's actually more popular than the commercial DataGrip among my colleagues and me. HeidiSQL is perceived to be more flexible.
One thing where HeidiSQL is lacking though is parameters in statements. We have many statements in applications like this:
SELECT foo FROM bar WHERE baz = :foobarbaz
When you execute this statement in DataGrip, it lets you enter a value which is automatically replaced by DataGrip. This is especially helpful if there are many parameters. In HeidiSQL I use search and replace, but it's somewhat cumbersome. It would be great if HeidiSQL would also support this.
Attached is a screenshot of DataGrip parameter window. It shows the parameter name, real column name (if applicable) and the value that gets replaced.