Hi, All. Is there any tool or way to inspect BLR for query or SP?
Or
I must study sources to understand principles of it's buiding? I want
to realize exactly what is the difference between

1.
Select T1.<something>, T2.Column
From T1 Left Join T2 On T1.Col1=T2.Col1
2.
Select T1.<something>, (Select Column From T2 Where T2.Col1=T1.Col1)
From T1
3.
Create SP
Returns (<something>, Column)
As
Declare Variable Col1;
Begin
For Select T1.<something>, T1.Col1 Into <something>, :Col1
Do
begin
Select Column From T2 Where Col1=:Col1 Into :Column;
Suspend;
end
End

and what should be faster and why. Or someone wise will be so kind to
explain?