How do I TryParse in SQL 2000? - tsql

Question

I have a stored procedure in an old SQL 2000 database that takes a comment column that is formatted as a varchar and exports it out as a money object. At the time this table structure was setup, it was assumed this would be the only data going into this field. The current procedure functions simply this this:
SELECT CAST(dbo.member_category_assign.coment AS money)
FROM dbo.member_category_assign
WHERE member_id = #intMemberId
AND
dbo.member_category_assign.eff_date <= #dtmEndDate
AND
(
dbo.member_category_assign.term_date >= #dtmBeginDate
OR
dbo.member_category_assign.term_date Is Null
)
However, data is now being inserted into this column that is not parsable to a money object and is causing the procedure to crash. I am unable to remove the "bad" data (since this is a third party product), but need to update the stored procedure to test for a money parsable entry and return that.
How can I update this procedure so that it will only return the value that is parsable as a money object? Do I create a temporary table and iterate through every item, or is there a more clever way to do this? I'm stuck with legacy SQL 2000 (version 6.0) so using any of the newer functions unfortunately is not available.

Answer 1

Checking for IsNumeric may help you - you can simply return a Zero value. If you want to return a 'N/a' or some other string value
I created the sample below with the columns from your query.
The first query just returns all rows.
The second query returns a MONEY value.
The third one returns a String value with N/A in place of the non-integer value.
set nocount on
drop table #MoneyTest
create table #MoneyTest
(
MoneyTestId Int Identity (1, 1),
coment varchar (100),
member_id int,
eff_date datetime,
term_date datetime
)
insert into #MoneyTest (coment, member_id, eff_date, term_date)
values
(104, 1, '1/1/2008', '1/1/2009'),
(200, 1, '1/1/2008', '1/1/2009'),
(322, 1, '1/1/2008', '1/1/2009'),
(120, 1, '1/1/2008', '1/1/2009')
insert into #MoneyTest (coment, member_id, eff_date, term_date)
values ('XX', 1, '1/1/2008', '1/1/2009')
Select *
FROM #MoneyTest
declare #intMemberId int = 1
declare #dtmBeginDate DateTime = '1/1/2008'
declare #dtmEndDate DateTime = '1/1/2009'
SELECT
CASE WHEN ISNUMERIC (Coment)=1 THEN CAST(#MoneyTest.coment AS money) ELSE cast (0 as money) END MoneyValue
FROM #MoneyTest
WHERE member_id = #intMemberId
AND #MoneyTest.eff_date <= #dtmEndDate
AND
(
#MoneyTest.term_date >= #dtmBeginDate
OR
#MoneyTest.term_date Is Null
)
SELECT
CASE WHEN ISNUMERIC (Coment)=1 THEN CAST (CAST(#MoneyTest.coment AS money) AS VARCHAR) ELSE 'N/a' END StringValue
FROM #MoneyTest
WHERE member_id = #intMemberId
AND #MoneyTest.eff_date <= #dtmEndDate
AND
(
#MoneyTest.term_date >= #dtmBeginDate
OR
#MoneyTest.term_date Is Null
)

Answer 2

Apologies for making a new answer, where a comment would suffice, but I lack the required permissions to do so. Onto the answer to your question, I would only like to add that you should use the above ISNUMERIC carefully. While it works much as expected, it also parses things like '1.3E-2' as a value numeric, which strangely enough you cannot cast into a numeric or money without generating an exception. I generally end up using:
SELECT
CASE WHEN ISNUMERIC( some_value ) = 1 AND CHARINDEX( 'E', Upper( some_value ) ) = 0
THEN Cast( some_value as money )
ELSE Cast( 0 as money )
END as money_value