Ok, I am hoping someone could help me out here. I have a query which is not working properly and is driving me crazy.
I have two tables
data_table = my main working table
daily_removed = same structure as main table, but less records

what I would like to do is
update the column (Status) in the data_table, for all records where the PiNumber is listed in the daily_removed table

This is where it gets weird for me... when I do

Code MySQL:
select count(data_table.PiNumber) from data_table
inner join daily_removed ON
data_table.PiNumber=daily_removed.PiNumber

I get a total of 1528 (which is the correct number) of matching records in the two tables
But when I go to update the Status column using

Code MySQL:
UPDATE data_table
INNER JOIN daily_removed
ON data_table.PiNumber = daily_removed.PiNumber
SET data_table.Status='removed';

only 1214 Records get updated. '

Also, as a side note I added exactly 1214 records to the daily_removed table today ...

What could possibly be happening??
Let me know if I need to post additional info, but any advice would be greatly appretiated.