>Where the use of : is optional, as best practice should : be used or avoided.
>Or in such cases use of : is irrelevant in terms of performance.

Inside "pure" sql statements it is manadatory (to distinguish between parameter name and column name),
on other places it does not matter, the parser accepts both variants (and they are identical)

> 2. I'm appending two stored procedures, one omits colon (Para 3 below) and another uses colon (Para 4 below) for fetching
> exactly the same data. The FlameRobin's Statistics TAB output on running the procedures (Firebird 3 on Windows 7 32 Bit) is
> listed as under for both the procedures, please notice the difference (omitting colon appears to be lowering performance) :
>
> OMITS COLON:- USES COLON:-
>
> Executing statement... Executing statement...
> Statement executed (elapsed time: 0.000s). Statement executed (elapsed time: 0.000s).
> 16541 fetches, 2 marks, 5 reads, 2 writes. 760 fetches, 0 marks, 0 reads, 0 writes.
> 0 inserts, 0 updates, 0 deletes, 72 index, 8064 seq. 0 inserts, 0 updates, 0 deletes, 71 index, 264 seq.
> Delta memory: 170752 bytes. Delta memory: 126824 bytes.
> Total execution time: 0.174s Total execution time: 0.049s
> Script execution finished. Script execution finished.

The first execute is longer because it also includes starting the transaction, fetching metadata etc.

Ivan