I'm pulling data from an existing table using a stored procedure that has some yes or no choices that the user picks on the front end through a checkbox. I want to limit writing a bunch of different If statements for every choice they make.
This portion of my where clause works. Data is either Y or N for this column.
Where... and IsSigned = Case When #IncludeSigned = 'Y' then IsSigned else 'N' end
I would like to add to the where using is not null and not like if this is possible between the square brackets. So far I have
and SignatureType = case when #IncludeElectronic = 'Y' then Type else [NOT like electronic] end
also
and ReviewDate = Case When #HasReviewDate = 'Y' then [ReviewDate is not null] else null end
This may help you use AND/OR instead of case
where (ReviewDate is not null or #HasReviewDate = 'Y' ) And (....)
ie when #HasReviewDate = 'Y' query will return the records with ReviewDate is not null
and when #HasReviewDate != 'Y' then query will return the records with ReviewDate is null
think of it this way:-
Your first case statement has two possible results:-
IsSigned = 'Y'
IsSigned = 'N'
Your subsequent ones have problems as they don't make sense syntactically. So the second one as written returns
SignatureType = Type
SignatureType = [NOT like electronic]
and your third:
ReviewDate = [ReviewDate is not null]
ReviewDate = null end
SO the operator has to be before the case statement and apply to all of the results of the case statement.
For example
WHERE myfield not like CASE WHEN thatfield=1 THEN 'Fish' ELSE 'Chips END
would produce either
myfield not like 'Fish'
myfield not like 'Chips'
I believe you can not use in this way, apart of that, the impact that is not like can have inside your query can be high, my recommendation changes the strategy that you are using.
Related
I am trying to use the SUBSTR and NVL functions inside the case. The case is in the where clause of the select statement.
The code below gives the following error:
ORA-00905: missing keyword
AND ( CASE
WHEN SUBSTR(upper(p_open_invoice),1,1) = 'Y' THEN
NVL(P.AMOUNT_DUE_REMAINING,0) = 0
ELSE
1=1
END)
This looks like a syntax error around equal operator of NVL function.
That is not how case expressions work (in Oracle) -- there is no boolean type to return.
The simplest method is to remove the `case and express this as simple logic:
AND (SUBSTR(upper(p_open_invoice), 1, 1) <> 'Y' OR
COALESCE(P.AMOUNT_DUE_REMAINING, 0) = 0
)
If p_open_invoice can be NULL, you need to take that into account as well.
You cannot use a collation as a result for case..when statements, it's better converting the condition to
AND (( SUBSTR(upper(p_open_invoice),1,1) = 'Y' AND NVL(P.AMOUNT_DUE_REMAINING,0) = 0 )
OR SUBSTR(upper(p_open_invoice),1,1) != 'Y' )
If you're accustomed to programming in PL/SQL you may have seen that there's a BOOLEAN type in PL/SQL. However, this is not true in the Oracle database itself. The way I usually work around this is to use character expressions which return 'Y' or 'N' instead of TRUE or FALSE.
Keeping this in mind - if you really want to use a CASE expression similar to what you had originally you can use the following:
AND CASE
WHEN SUBSTR(upper(p_open_invoice),1,1) = 'Y'
THEN CASE
WHEN NVL(P.AMOUNT_DUE_REMAINING,0) = 0 THEN 'Y'
ELSE 'N'
END
ELSE 'Y'
END = 'Y'
Here the CASE expression returns either 'Y' or 'N', which is then compared with 'Y'.
So I have EXISTS in huge query which looks like this:
EXISTS(
SELECT
*
FROM
ExistTable
WHERE
ExTableFieldA = #SomeGuid AND
ExTableFieldB = MainTableFieldB AND
ExTableFieldA <> (
CASE
WHEN MainTableFieldZ = 10 THEN MainTableFieldYYY
ELSE NULL
END
)
)
The problem comes from ELSE part of CASE statement, this ExTableFieldA <> NULL will be always false. I could easily write another parameter #EmptyGuid and make it equal to '00000000-0000-0000-0000-000000000000' and everything will work but is this the best approach ?
Pretty much I want to execute another check into the exist for the small size of the records which return the "main" query.
How about removing the case and just using boolean logic?
WHERE ExTableFieldA = #SomeGuid AND
ExTableFieldB = MainTableFieldB AND
(MainTableFieldZ <> 10 OR ExTableFieldA <> MainTableFieldYYY)
I would also recommend that you qualify the column names by including the table alias.
Note: This does assume that MainTableFieldZ is not NULL. If that is a possibility than that logic can easily be incorporated.
ELSE NULL is implied even if you don't list it, but you could use ISNULL here.
ISNULL(ExTableFieldA,'') <> (
CASE
WHEN MainTableFieldZ = 10 THEN MainTableFieldYYY
ELSE ''
END
)
You may need to use some other value like 9999 instead of ''
I am creating a store procedure and i am wondering how can i add a case block in an Add statement inside the where statement.That case statement checks an input parameter and depending its value it will change the condition from greater that to smaller than and of course be added to the add conditions
So a part of the query is like:
WHERE
AND BM.Example1 IS NOT NULL
AND BM.Example2 IS NOT NULL
AND ( Case When #inputParamter= 'A' THEN AND BM.Example < 0 ELSE And BM.Example> 0 )
ORDER BY 'SEG' ASC, 'CCY' ASC
So by this approach i am thinking to extract an add statement depending on the input parameter but unfortunately i keep getting syntax errors.
Is that possible?
Yepp, just use this:
AND (( #inputParamter= 'A' AND BM.Example < 0) OR ( #inputParamter<>'A' AND BM.Example> 0) )
However, be carefull with NULL, you have to put it in the logic as a third option.
here is a similar answer using case
AND ( Case When #inputParamter = 'A' AND BM.Example < 0 THEN 'Y'
When #inputParamter <> 'A' AND BM.Example > 0 THEN 'Y' ELSE 'N' END = 'Y')
Why does this case statement not work? My table is defined as below. I want the case to return true when M = "M" or false if it is not. Something does not seem to look right with this CASE statement but this is the simple case statement. But I thought that could be as many WHEN values as needed but in this cases there is only True or False and it does not appear that there could be anything different.
The input should be all of the M column in the row. I am expecting the output to be one row since I only have one row that has an M value in the column. I am not certain if the case statement should return false in this case.
CASE M = "M <-- is this is what the criteria is based on
I found that this is not the case however from the post below. When i meant that this did not look right I was referring two the fact that the WHEN portion of the code
WHEN true THEN something
just did not look like it normally does.
Code:
select CASE M = "M"
WHEN true THEN "PPP"
WHEN false THEN "False -- Look Again!"
ELSE "Not Found"
END
from Bat;
Image:
New Code:
select *,
CASE
WHEN M = 'M' THEN
Case
when O = 'O' then 'you found a double (MM)' <--Compiles but does not show result
End
WHEN M is null THEN 'False -- Look Again!'
END as 'What is this value'
from Bat;
That fixed the first problem but you can embed case statements N deep I would think so if i search again on O it should return a correct. But the first case returns only one record. So my second case would have to search in the record correct.
The normal way to write this is:
select (CASE WHEN M = 'M' THEN 'PPP'
WHEN M <> 'M' THEN 'False -- Look Again!'
ELSE 'Not Found'
END)
from Bat;
or:
select (CASE WHEN M is null then 'Not Found'
WHEN M = 'M' THEN 'PPP'
ELSE 'False -- Look Again!'
END)
from Bat;
If I had to guess, your version has unexpected behavior for NULL values, but it is hard to say without knowing what you expect or what it is doing.
Change it like this
select CASE
WHEN M = 'M' THEN 'PPP'
WHEN M is null THEN 'False -- Look Again!'
ELSE "Not Found"
END
from Bat;
I am working on a select statement in SQL and am running into issues trying to create a where clause that includes a case statement or an if else statement. I want to select records based on the value of a variable. If the variable is 'True' then only return records from the select statement where a column is null. If the variable is not 'True' then return all records regardless if that columns is null.
Any tips on how to do this?
Below is a simple example of what i am trying to do:
declare #option1 as varchar(5)
--This can be True or False so to test i just put the Set option below
set #option1 = 'True'
Select a,b,c,d...
from ...
where d = case when #option1 = 'True' then NULL End
This is the part where i do not know what to do. I only need to filter out the records if the variable is 'True' so not sure what to put in the else section of the case.
You can't test for d = NULL as your CASE statement does because that will always return false since NULL is not equal to NULL (unless you set ANSI_NULLS to 'off').
The simplest thing to do would be to change the WHERE clause to this:
WHERE #option1 = 'False' OR d IS NULL
If you prefer to use a CASE statement for some reason, you can write it like this:
WHERE 1 = CASE WHEN #option1 = 'False' THEN 1
WHEN #option1 = 'True' AND d IS NULL THEN 1
ELSE 0
END
This:
UPDATE: PinnyM has straightened me out on this. I am leaving my embarrassing logically flawed argument here for the education of the masses. The solution I propose below after "Try this" is certainly still valid, but PinnyM's solutions is by far more elegant and should be used.
WHERE #option1 = 'False' OR d IS NULL
Will always return all the results given his current select statement (assuming #Option1 is simply a flag parameter passed in).
Try this:
SELECT a, b, c, d
WHERE
-- Returns only rows where d is null (if #Option1 is True)
(#Option1 = 'True' AND d IS NULL)
OR
-- returns all the rows (if #Option1 is False)
(#Option1 = 'False')