CODEWITHSUNDEEP
sqlcount
Mike Reed
Mike Reed

Reputation: 33

Updating a field based on a count of records from a different table

I need to set a value to 1 in table where the count for a given role in another table is > 1.

The table cursillo.members has fields memid and hsd. Table cursillo.teams has fields memid (the link between the two) a field called movement and another called role.

What I am trying to accomplish is something similar to this:

update cursillo.members_eligible p, cursillo.teams pp
   set p.hsd=1     
 where p.memid = pp.memid AND (pp.role = 'HSD' OR pp.role = 'SD')
   and pp.movement = 'Cursillo' AND count(pp.role) > 1;

or this:

update members_eligibile
   set hsd=1 
  from teams 
 where teams.memid=members_eligible.memid 
   and (teams.role = 'HSD' OR teams.role = 'SD')  
   and teams.movement = 'Cursillo' 
   and count(teams.role) > 1;

In other words if a given memid has more than one record in the cursillo.teams table where the value of the role is equal to either HSD or SD, then set cursillo.members_eligible.hsd to 1.

I can't figure out to handle the count() part.

Thanks, Mike Reed

Upvotes: 3

Views: 173

Answers (2)

ContextSwitch
ContextSwitch

Reputation: 2837

Possible duplicate question:

MySQL - Using COUNT(*) in the WHERE clause

Try using the 'having' keyword

Here's the relevant section from the linked answer (in this case, a select statement):

select gid
from `gd`
group by gid 
having count(*) > 10
order by lastupdated desc

It looks like 'having' can only be used in select statments though: http://www.mysqltutorial.org/mysql-having.aspx

So you may need to have your update's where clause include a select statement:

update members_eligibile
   set hsd=1 
  from teams 
 where teams.memid=members_eligible.memid 
   and (teams.role = 'HSD' OR teams.role = 'SD')  
   and teams.movement = 'Cursillo' 
   and members_eligible.memid IN
   (SELECT members_eligible.memid from members_eligible where teams.memid=members_eligible.memid  having count(teams.role) > 1);

You will have to adjust the select statement, I haven't tested it

Upvotes: 1

Oleksandr Fedorenko
Oleksandr Fedorenko

Reputation: 16904

SQL Server 2005+

UPDATE x
SET x.hsd = 1
FROM (SELECT e.hsd, COUNT(*) OVER (PARTITION BY t.role) AS cnt
      FROM teams t JOIN members_eligibile e ON t.memid = e.memid
      WHERE (t.role = 'HSD' OR t.role = 'SD') AND t.movement = 'Cursillo') x
WHERE x.cnt > 1

Upvotes: 0

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