CASE statement: Inconsistent conversion fail error - varchar to int - sql

Question

SELECT
CASE
WHEN Employees.first_name IS NULL
OR Employees.first_name = 'x' THEN Employees.last_name
WHEN Employees.credentials IS NULL THEN Employees.last_name + ', ' + Employees.first_name
ELSE Employees.last_name + ', ' + Employees.first_name + ' - ' + Employees.credentials
END,
Employees.num3,
Employees.address1 + ' ' + Employees.city + ', ' + Employees.state + ' ' + Employees.zip,
Employees.work_phone,
CASE
WHEN Clients.age <= 18 THEN 'Youth'
ELSE 'Adult'
END,
Clients.client_id,
Clients.last_name + ', ' + Clients.first_name,
ClientVisit.cptcode,
ClientVisit.visittype,
ClientVisit.rev_timeout,
ClientVisit.timein,
ClientVisit.duration,
SUM(CASE
WHEN ClientVisit.cptcode = 90791 THEN 200
WHEN ClientVisit.comb_units = 1 THEN 85.67
ELSE ClientVisit.comb_units * 21.4175
END),
DATEDIFF(d, ClientVisit.rev_timeout, ClientVisit.signature_datetime)
FROM dbo.ClientVisit
INNER JOIN dbo.Employees
ON (
ClientVisit.by_emp_id = Employees.emp_id
)
INNER JOIN dbo.Programs
ON (
ClientVisit.program_id = Programs.program_id
)
INNER JOIN dbo.Clients
ON (
Clients.client_id = ClientVisit.client_id
)
WHERE (
ClientVisit.rev_timeout BETWEEN '20160401 11:40:00.000' AND '20160415 11:40:16.000'
AND Programs.program_desc IN ('Off Panel')
AND ClientVisit.non_billable = 0
AND ClientVisit.cptcode NOT IN ('00000', '0124', '100', '1001', '101', '102', '103', '80100', '9079', '99999')
AND Employees.num3 IS NOT NULL
)
GROUP BY
CASE
WHEN Clients.age <= 18 THEN 'Youth'
ELSE 'Adult'
END,
CASE
WHEN Employees.first_name IS NULL
OR Employees.first_name = 'x' THEN Employees.last_name
WHEN Employees.credentials IS NULL THEN Employees.last_name + ', ' + Employees.first_name
ELSE Employees.last_name + ', ' + Employees.first_name + ' - ' + Employees.credentials
END,
DATEDIFF(d, ClientVisit.rev_timeout, ClientVisit.signature_datetime),
ClientVisit.cptcode,
Clients.last_name + ', ' + Clients.first_name,
Clients.client_id,
Employees.address1 + ' ' + Employees.city + ', ' + Employees.state + ' ' + Employees.zip,
Employees.work_phone,
ClientVisit.duration,
ClientVisit.visittype,
ClientVisit.rev_timeout,
ClientVisit.timein,
Employees.num3
Gives me the Error:
Conversion failed when converting the varchar value 'H2019' to data
type int.
I'm unable to locate specifically where this conversion is taking place and what could be a possible fix.
EDIT: Located problem in cptcode column which has alphanumeric entries. However, changing date ranges in WHERE clause gives results for some dates and not for others.

Answer 1

when you use
"ClientVisit"."cptcode" = 90791
the data type of 90791 will be integer. If you replace it with
"ClientVisit"."cptcode" = '90791'
both sides of the equation will be characters. You can also do something like:
"ClientVisit"."cptcode" = CAST(90791 AS VARCHAR(20))
The reasons for your problem is that SQL Server will do an implicit conversion. In this case to integer as Integer has a higher Data Type Precedence than (n)(var)char data types.
Of course I do not know your data but I guess there are data ranges where there is only numeric values for cptcode. So your code will work for them but not if you hit something like e.g. H006
Hope that helps ;-)

Answer 2

Comment out all the colums in the select segment and start ucommenting them one by one while executing the select each time. When you uncomment the problematic line, you'll find the source of the error.
BTW: I'm guessing the problem is in "ClientVisit"."cptcode" = 90791.