using min and DATE() in SQL

Question

I am running an SQL Query and i want to use min() and DATE()

i tried:

and min(DATE(datetime)) = '".date("Y-m-d")."'

but that does not work, what should i be using?

the full query i have tried is:

select 
  min(datetime) as d, 
  ticketnumber 
from ticket_updates 
where type = 'update' 
and min(DATE(datetime)) = '".date("Y-m-d")."' 
group by ticketnumber

i have also tried:

select 
  min(datetime) as d, 
  ticketnumber 
from ticket_updates 
where type = 'update' 
and min(datetime) >= '".date("Y-m-d 00:00:00")."' 
and min(datetime) <= '".date("Y-m-d 23:59:59")."'
group by ticketnumber

but i get an error saying:

Invalid use of group function

Answer 1

There is no need to use the min function in your where clause.

I've also changed the where to use between for readability.

select 
  min(datetime) as d, 
  ticketnumber 
from ticket_updates 
where type = 'update' 
and datetime between'".date("Y-m-d 00:00:00")."' 
                and '".date("Y-m-d 23:59:59")."'
group by ticketnumber

This code will find the lowest date/time for each ticket number on the date provided.

Check out this FIDDLE

Answer 2

If you want the earliest date time, then use a having clause:

select min(datetime) as d, ticketnumber 
from ticket_updates 
where type = 'update' 
group by ticketnumber
having min(DATE(datetime)) = '".date("Y-m-d")."'

These seems rather strange as a construct, because the min is going to get the date you are entering. All the work is in the filtering.

Answer 3

Wrap your query to another:

SELECT d, ticketnumber FROM(
  select 
  min(datetime) as d, 
  ticketnumber 
  from ticket_updates 
  where type = 'update' 
  group by ticketnumber
) t
WHERE d between '...' and '...'

FIDDLE

Answer 4

If you would like to get the min date you need to have a column to group by. For example,

Select id, Min(Date) as Min_date
from mytable group by id

Can you provide more details so that we can try to resolve this?