The 'JQL Query' compares the number of issues returned from the JQL query against predefined conditions like:
Find at least one issue
Must not find any issue
Compare with a particular number
Some of the simple things you would do with the JQL Precondition, you might also achieve with the Value Field Precondition. Choose the approach that is the simplest for you and your Jira admin colleagues.
You must write the 'JQL Query' and choose one option about the number of issues found. For example:
With this precondition, the post function will be only executed for bugs. You won’t will need a separate workflow (and special workflow scheme configuration), when you only want one post function to perform differently for a particular issue type.