Left Outer Join
Hi~
Big Issue in "Left Outer Join"
"mydata" table schema
pk1 as varchar , pk2 as varchar,pk3 as datatime, value1 as int,value2 as int
Left Outer Join SQL
select a.pk1,a.pk3,a.value1,a.value2,b.value1,b.value2
from mydata as a
left outer join mydata as b
on (a.pk1=b.pk1 and b.pk2='data2' and a.pk3=b.pk3)
where a.pk1='abc' and a.pk2='data1' and a.pk3>='2016/5/3 15:00' and a.pk3<='2016/5/3 16:00'
it's OK when pk3 us >= & <= , select result
abc ,2016/5/3 15:00 , 1,1,2,2
abc ,2016/5/3 15:30 , 2,2,9,9
abc ,2016/5/3 16:00 , 3,3,12,12
but when i use a.pk3='2016/5/3 15:00', select result
abc ,2016/5/3 15:00 , 1,1,null,null
i try it at MS SQL, select result
abc ,2016/5/3 15:00 , 1,1,2,2
what's the different ??? and how should i fix MySQL sql stirng ??