I'm looking to make part of my query more performant by cutting down on the number of case statements I use. I have a select statement as below currently:
SELECT
ID,
CASE WHEN sum(Value1) > 0 THEN 1 ELSE 0 END as [Value1],
CASE WHEN sum(Value2) > 0 THEN 1 ELSE 0 END as [Value2],
CASE WHEN sum(Value3) > 0 THEN 1 ELSE 0 END as [Value3],
CASE WHEN sum(Value4) > 0 THEN 1 ELSE 0 END as [Value4],
....
FROM table
Essentially I want the query to simply produce a boolean, either a 0 or a 1, but the case statements have tripled the runtime for my query which is less ideal. Is there a way I can force a boolean output or set a maximum value for my select and trim away the cases?
As John Cappelletti has provided, the expected output of limiting an INT value into a Boolean 0/1 output is achieved via the SIGN function. This reduces the runtime for the query significantly compared to the case statement.
Related
Trying to return a column, giving 1, when column1 is NOT NULL and different than 0. So far managed to do this:
MAX(CASE WHEN column1 IS NOT NULL
THEN CASE WHEN column1 <> 0 THEN 1 ELSE 0 END
ELSE 0 END)
Getting this error:
SELECT Failed. 2620: The format or data contains a bad character.
It works quite ok with NOT NULL as a single condition, though.
I'm not sure why you need to nest anything, but it looks like you're missing the non-equality sign.
You might try,
CASE
WHEN column1 IS NOT NULL AND column1 <> 0
THEN 1
ELSE 0
END
Alternatively, this will produce the same result as an OR operator, where, but CASE executes the WHEN clauses in order.
CASE
WHEN column1 IS NOT NULL
THEN 1
WHEN column1 <> 0
THEN 1
ELSE 0
END
But in your description, it sounds like you wanted BOTH conditions to be true, so it doesn't make sense to nest or use multiple WHEN statements, because you can just connect them together with AND
I need to verify one column only has numbers(integer number only) in oracle . If yes then set flag as 1 otherwise 0. I am trying to use below reg_exp( but it sets flag to 1 even for hyphen ):
CASE WHEN REGEXP_LIKE(Column_name,'\d\) THEN 1 ELSE 0 END
Examples:
12345 should ( this is working and above code is setting flag to 1)
-1234 should set flag to 0 ( above code is setting it to 1)
abcd should set flag to 0 ( above code is working correct in this case)
123.23 should set flag to 0
If you want check if contain only digit or not try
CASE WHEN REGEXP_LIKE(Column_name, '^[[:digit:]]+$') THEN 1 ELSE 0 END ;
You may use TRANSLATE function
SELECT case when TRANSLATE(Column_name, 'X0123456789', 'X') is null
then 1
else 0
end
FROM t;
I like to check the length of a specified fields is x length and available value is a numeric value
i can do this by using two separate case statements like below
(case when len(columnA) = 10 then 0 else 1 end)+
(case when IsNumeric(columnA) = 1 then 0 else 1 end)+
(case when len(columnB) = 8 then 0 else 1 end)+
(case when IsNumeric(columnB) = 1 then 0 else 1 end)
is there any better approach as i need to this for more than 40 columns and their datatype is varchar and each of the column will have specific length.
using some short cut to reduce above two case statements into one line
If you only care that a column is invalid and are less interested in which criteria it failed on then you could just put both criteria into the one case statement as
(case when len(columnA) = 10 and IsNumeric(columnA) = 1 then 0 else 1 end)
In regards to the issue Sean raised, ISNUMERIC only confirms the value can be converted to a numeric datatype so commas and periods are valid too. you could do a check for any single character that isn't in the range of numbers
case when len(columnA) = 10 and ColumnA not like '%[^0-9]%' then 0 else 1 end
It is a little ugly because we have to say is not [not in range], so you might want to change the logic a bit.
I want to check for a pattern in sql such that if there is anything in that expression (or table cell) other than numeric it should return 1. If that whole cell has only numeric values it should return 0
eq:
case when '200290' like [anything other than numbers]
then 1
else o
In SQL Server, you can use something like (I'm not writing the whole function for you):
DECLARE #t varchar(100) = '231321321321'
SELECT CASE WHEN PATINDEX('%[^0-9]%', #t) > 0 THEN 1
ELSE 0 END
SELECT CASE CHARACTERS(OTRANSLATE(<your_string>,'a1234567890','a'))
WHEN 0 THEN 0 ELSE 1 END;
Ex.:
-- BTEQ Enter your SQL request or BTEQ command:
SELECT CASE CHARACTERS(OTRANSLATE('12345','a1234567890','a'))
WHEN 0 THEN 0 ELSE 1 END;
* Query completed. One row found. One column returned.
* Total elapsed time was 1 second.
<CASE expression>
------------------
0
SELECT CASE CHARACTERS(OTRANSLATE('1a23b45c','a1234567890','a')) WHEN 0 THEN 0 ELSE 1 END;
* Query completed. One row found. One column returned.
* Total elapsed time was 1 second.
<CASE expression>
------------------
1
I have seen similar questions asked elsewhere on this site, but more in the context of optimization.
I am having an issue with the order of execution of the conditions in a WHERE clause. I have a field which stores codes, most of which are numeric but some of which contain non-numeric characters. I need to do some operations on the numeric codes which will cause errors if attempted on non-numeric strings. I am trying to do something like
WHERE isnumeric(code) = 1
AND CAST(code AS integer) % 2 = 1
Is there any way to make sure that the isnumeric() executes first? If it doesn't, I get an error...
Thanks in advance!
The only place order of evaluation is guaranteed is CASE
WHERE
CASE WHEN isnumeric(code) = 1
THEN CAST(code AS integer) % 2
END = 1
Also just because it passes the isnumeric test doesn't guarantee that it will successfully cast to an integer.
SELECT ISNUMERIC('$') /*Returns 1*/
SELECT CAST('$' AS INTEGER) /*Fails*/
Depending upon your needs you may find these alternatives preferable.
Why not simply do it using LIKE?:
Where Code Not Like '%[^0-9]%'
Btw, either using my solution or using IsNumeric, there are some edge cases which might lead one to using a UDF such as 1,234,567 where IsNumeric will return 1 but Cast will throw an exception.
Why not use a CASE statement to say something like:
WHERE
CASE WHEN isnumeric(code) = 1
THEN CAST(code AS int) % 2 = 1
ELSE /* What ever else if not numeric */ END
You could do it in a case statement in the select clause, then limit by the value in an outer select
select * from (
select
case when isNum = 1 then CAST(code AS integer) % 2 else 0 end as castVal
from (
select
Case when isnumeric(code) = 1 then 1 else 0 end as isNum
from table) t
) t2
where castval = 1