>>If you would add a WHERE condition on the columns from the child table, it'll kill LEFT JOIN and it'll be like INNER JOIN.
>>
>>>Thanks Sergey. I thought that was correct. Something else was causing issues with the result.
>
>Thats correct I had done that.
>
>I have a table of parameters that I added to the select.

I have a blog on this exact topic, take a look

Why LEFT JOIN does not bring all records from the LEFT table