Re: max(DateField)+C <> max(DateField+C)

[Tom Byars]

Here's another inconsistency for you Peter.

select * from (select date('2012-02-17') as DateFld) tbl1 left join (select date('2012-02-17') as DateFld, 'X' as StrFld) tbl2
using (DateFld)
where DateFld='2012-02-17 00:00:00';

This returns values ('2012-02-17', NULL) which implies MySQL assumes
tbl1.DateFld = '2012-02-17 00:00:00'
but
tbl2.DateFld <> '2012-02-17 00:00:00'.

Change the left join to an inner join as in

select * from (select date('2012-02-17') as DateFld) tbl1 inner join (select date('2012-02-17') as DateFld, 'X' as StrFld) tbl2
using (DateFld)
where DateFld='2012-02-17 00:00:00';

and it returns the values ('2012-02-17', 'X')

Now it seems MySQL recognises that
tbl1.DateFld = '2012-02-17 00:00:00'
and
tbl2.DateFld = '2012-02-17 00:00:00'