Error in nested SQL statement - sql

Question

Can someone help me fix this SQL statement? I have 2 tables... trying to get a list of all records in table 1 (c) along with a count (if any) of matching records in table 2 (cp_docs).
SELECT TOP 100 c.cal_procedure ,
c.description ,
c.active ,
c.create_user ,
c.create_date ,
c.edit_user ,
c.edit_date ,
c.id,
cp_docs.cpd
FROM cal_procedure c
OUTTER JOIN (select cal_procedure as cp, count(id) as cpd
from cal_procedure_doc
group by cal_procedure) cp_docs
ON cp_docs.cp = c.cal_procedure
Thanks,
Tracy

Answer 1

Hard to say without the error message but your outer join has a couple issues.
OUTER is incorrectly written at OUTTER
Your OUTER keyword needs to be prefixed with LEFT OR RIGHT. With the logic in your query you want likely want LEFT
Fixed SQL:
SELECT TOP 100 c.cal_procedure ,
c.description ,
c.active ,
c.create_user ,
c.create_date ,
c.edit_user ,
c.edit_date ,
c.id,
cp_docs.cpd
FROM cal_procedure c
LEFT OUTER JOIN (select cal_procedure as cp, count(id) as cpd
from cal_procedure_doc
group by cal_procedure) cp_docs
ON cp_docs.cp = c.cal_procedure
Now in your query, you could get null values in the cpd column if there were no values in the cal_prodcedure_doc table. If you look at Max's answer, you would get 0's instead. If you wanted to use your current approach but have the zero's display you would need to wrap cp_docs.cpd in a coalesce function
coalesce(cp_docs.cpd, 0)
In the end I think Max's answer is easier to read and probably the way I would write this query as I think it's easier to read. If the tables are huge you may want to check how each performs to see one is better than the other.

Answer 2

You can just add a subquery to the SELECT clause. It's cleaner than joining a temp table. If you try to read someone else's query to figure out how a calculation is done, you'll start with the SELECT statement. If the select statement points you to a table alias (e.g. cp_docs), you need to find the table in the FROM clause... etc. The execution plans are almost identical; the proposed SELECT clause subquery actually eliminates one innocuous Compute Scaler step.
SELECT c.cal_procedure ,
c.description ,
c.active ,
c.create_user ,
c.create_date ,
c.edit_user ,
c.edit_date ,
c.id,
(SELECT COUNT(*) FROM cal_procedure_docs where cal_procedure = c.cal_procedure) AS cpd
FROM cal_procedure c

Answer 3

Perhaps you want outer apply :
SELECT TOP 100 c.cal_procedure, c.description, c.active, c.create_user,
c.create_date, c.edit_user, c.edit_date, c.id, cp_docs.cpd
FROM cal_procedure c OUTER APPLY
(select count(id) as cpd
from cal_procedure_doc
where cal_procedure = c.cal_procedure
) cp_docs
ORDER BY ? ? ? ;