Syntax for advanced search on iPhone

[Tom]

I'm finding MLO's iPhone syntax for a search very difficult.

I'm wanting to find every task that starts with one of several different strings AND is either Completed Today or has no Completion Date.

So like this:

(Caption starts with "Sun" OR

Caption starts with "Mon" OR

Caption starts with "Tue")

AND

(Completion Date is Today OR

Completion Date does not exist)

Thanks in advance for any help you can give me.