SQL help - count all serialNumbers except those with specific cases - sql

Question

I need help with writing a case statement inside of a where clause.
Let's say we have a bunch of serial numbers stored in a database.
They are prefixed with some letters to denote their group.
Here is what I need to accomplish:
Exclude all serial numbers that begin with 'GIU' unless some conditions apply:
If the serial number starts with GIU and is 15 chars long and the last 4 numbers are less than 5000, then exclude it, otherwise include it.
If the serial number starts with GIU and is 16 chars long and the last 5 numbers are less than 10000, then exclude it, otherwise include it.
ex. GIU930798246071 should be included because: begins with GIU -> 15 chars long -> 6071 > 5000.
ex2. GIU9307982410621 should be included because it begins with GIU -> 16 chars long -> 10621 > 10000.
ex3. GIU930798243071 should be excluded because 15 chars long -> last 4 digits (3071) < 5000.
If I wanted to run a query to count these results, I tried:
select count(serialNum)
FROM serialNumbers
WHERE serialNum not like (
case when LEN(serialNum) = 15 and SUBSTRING(serialNum, 1, 3) = 'GIU' and RIGHT(serialNum, 4) < 5000 then 'GIU%'
when LEN(serialNum) = 16 and SUBSTRING(serialNum, 1, 3) = 'GIU' and RIGHT(serialNum, 5) < 10000 then 'GIU%' end)
I'm trying to append the results of the case statement to the not like statement if those conditions apply.
Running the query returns null, so I know some part of the case is ruining the entire query.
Also, there are other serialNum who prefix start with other letters which it should also be counting.
I basically just need it to count all serialNums except the ones that start with GIU for these specific cases.
Any and all help is appreciated.

Answer 1

So, what you could do is do a column to confirm what you are looking for (or not). Once you get it confirmed, then do it. By taking a slight shift from what Bart provided, you need to explicitly INCLUDE the "GIU" as part of the condition
what DONT you want...
( left( serialNum, 3 ) = 'GIU'
AND LEN(serialNum) = 15
AND CAST(RIGHT(serialNum, 4) AS INT) < 5000 )
OR
( left( serialNum, 3 ) = 'GIU'
AND LEN(serialNum) = 16
AND CAST(RIGHT(serialNum, 5) AS INT) < 10000 )
So if the where clause was the ABOVE, you would ONLY get those in the excluded realm. So to invert this,
WHERE NOT ( above condition1 or condition2 )
thus
WHERE
NOT (
( left( serialNum, 3 ) = 'GIU'
AND LEN(serialNum) = 15
AND CAST(RIGHT(serialNum, 4) AS INT) < 5000 )
OR
( left( serialNum, 3 ) = 'GIU'
AND LEN(serialNum) = 16
AND CAST(RIGHT(serialNum, 5) AS INT) < 10000 )
)

Answer 2

Sometimes things might be simpler than you think. I rearranged your WHERE-clause just to match the specs you provide in the description. I get something like this.
select count(serialNum)
FROM serialNumbers
WHERE
serialNum not like 'GIU%' or
(LEN(serialNum) = 15 and CAST(RIGHT(serialNum, 4) AS INT) >= 5000) or
(LEN(serialNum) = 16 and CAST(RIGHT(serialNum, 5) AS INT) >= 10000)
Does this help?
Note that I explicitly casted the last 4 or 5 positions of the serial number to an integer. I assume the query will fail if those positions are not numeric. There are solutions for such cases as well, but for clarity I omitted them here.
Edit:
There is an alternative solution, assuming that the above query's logic is correct.
A 4-digit number larger than or equal to 5000 has the form 5nnn, 6nnn, 7nnn, 8nnn, or 9nnn. A 5-digit number larger than or equal to 10000 does not start with a 0.
Using LIKE pattern matching for those cases, you could probably use the following query as well:
select count(serialNum)
FROM serialNumbers
WHERE
serialNum not like 'GIU%' or
(LEN(serialNum) = 15 and serialNum like '%[56789]___') or
(LEN(serialNum) = 16 and serialNum like '%[^0]____')
Note that I used an underscore in the LIKE-patterns here to match any single character. I simply assume that they will actually be digits.
Edit 2:
Sorry. Re-reading your question, I probably got the last digits checking the wrong way around. Fixed it.