Can't understand lack of matching records using left join

[John Choiniere]

Hi folks,

I feel really stupid asking this, but I CANNOT figure out why this is returning all null values.

Table z has fields player, fg_id, bpro_id, and a bunch of projected numbers. Table s has fields fg_id and a bunch of projected numbers. Table p had fields bpro_id and a bunch of projected number.  z.fg_id and z.bpro_id are varchar(255); s.fg_id is varchar(255); p.bpro_id is INT(11).

Running the query

select

   z.player,

   p.*

from z

left join p

on z.bpro_id = p.bpro_id

Returns exactly what I expect; running

select

   z.player,

   s.*

from z

left join s

on z.fg_id = s.fg_id

returns only NULL values.  I've checked in excel with vlookup that the fg_id values match between the two csv files used for import.  I can't figure out why everything's null.  Anyone have any thoughts? Am I missing something obvious?