Creating INNER Joins with IIF - sql

Question

I am trying to join three tables using and inner join and have the contents of one change colour if an e-mail has been sent.
Below is my query
SELECT IIF(COUNT Holdsent.job)>0, #STD, #RED) AS Colour, jobs.job, jobs.jobstatus, jobs.client, jobs.logdate
FROM jobs INNER JOIN clients ON clients.client = jobs.client INNER JOIN holdsent ON holdsent.job = jobs.job
WHERE (jobs.jobstatus = 'HOLD' OR jobs.jobstatus = 'CLIHOLD')
Below is the error I receive
Expected lexical element not found: (missing ( in aggregate function
[Parsing Expression (column1 in the SELECT clause)] -- Location of
error in the SQL statement is:1 SELECT IIF(COUNT
Holdsent.job)>0,#STD, #RED) AS COLOUR,jobs.job,
jobs.jobstatus,jobs.client,jobs.logdate FROM jobs INNER JOIN clients
ON clients.client = jobs.client INNER JOIN holdsent ON holdsent.job =
jobs.job WHERE (jobs.jobstatus = 'HOLD' OR jobs.jobstatus =
'CLIHOLD')
I am new to SQL and can do basic queries, but am not clear on IIF. Thank you in advance for any help you can provide.

Answer 1

iif is a special function from MS Access, which SQL Server has started supporting with the most recent version. The correct SQL form is the case statement. An improved version of your query, written in standard SQL, is:
SELECT (case when COUNT(hs.job)>0 then #STD else #RED end) AS Colour,
j.job, j.jobstatus, j.client, j.logdate
FROM jobs j INNER JOIN
clients c
ON c.client = j.client INNER JOIN
holdsent hs
ON hs.job = j.job
WHERE j.jobstatus in ('HOLD', 'CLIHOLD')

Answer 2

Sorry, I didnt mock up test tables for this, but I think you want to subquery against your holdsent table to get the count value into the main query, then use three parameters in your IIF() function. I didnt make a test case, but I think this will suit your needs:
SELECT IIF((isnull(holdsentCount.jobCount,0)>0, #STD, #RED) AS Colour
, jobs.job
, jobs.jobstatus
, jobs.client
, jobs.logdate
FROM jobs
JOIN clients
ON clients.client = jobs.client
LEFT JOIN (select holdsent.job
, count(*) as jobCount
from holdsent
group by holdsent.job ) as holdsentCount
ON holdsentCount.job = jobs.job
WHERE (jobs.jobstatus = 'HOLD' OR jobs.jobstatus = 'CLIHOLD')
Also, wrap the holdsentCount.jobCount with isnull() so that it returns 0 if it isn't returned in the subquery.
EDIT: I dont know what '#STD' or '#RED' are so I left them as-is.