I have an SQL query where the case expression is not working because I am getting the NULL value.
Any idea how to fix this?
select
td.reportEndDate,
CASE td.originalLinearAirDate
WHEN NULL THEN '12345678'
END As originalLinearAirDate
from
FROM DBA.Telecast td
where id = 2
order by
td.reportEndDate,
originalLinearAirDate;
You can use isnull
select
td.reportEndDate,
CASE WHEN td.originalLinearAirDate IS NULL THEN '19000101'
ELSE td.originalLinearAirDate
END As originalLinearAirDate
from
FROM DBA.Telecast td
where id = 2
order by
td.reportEndDate,
originalLinearAirDate;
You can use COALESCE() :
SELECT td.reportEndDate,
COALESCE(td.originalLinearAirDate, '12345678') AS originalLinearAirDate -- Use default date instead of '12345678'
FROM DBA.Telecast td
WHERE id = 2
ORDER BY td.reportEndDate, originalLinearAirDate;
In your case expression you didn't specified ELSE part hence you got NULL.
However, case expression will only return one type. So, you should check code or do necessary conversation.
The problem is the NULL comparison. The comparison is never true, even when used from comparison in a CASE expression.
If you wanted to do this using CASE, then you need to use IS NULL:
(CASE WHEN td.originalLinearAirDate IS NULL
THEN '12345678'
END) As originalLinearAirDate
If you want to return the original value in this case, you need an ELSE:
(CASE WHEN td.originalLinearAirDate IS NULL
THEN '12345678'
ELSE td.originalLinearAirDate
END) As originalLinearAirDate
Note that this will return an error if the column is really a DATE, because '12345678' cannot be converted to a date.
This version is better expressed using COALESCE():
COALESCE(td.originalLinearAirDate, '12345678')
Related
I am trying to run this logic, where i get output as follows,
My code to get the below output field is shown below
select max(dtm) over (partition by name ,id )-current_date from mm
output
-4168
-4168
-4168
-4127
what i want is to run this logic along with 'case when' statement so i tried:
case when max(dtm) over (partition by name ,id )-current_date then 'yes'
else 'No' end as output
from mm
but i get an error as follows, not sure what went wrong in this logic.
Operator 'is true' for type 'long' not found
There are two forms of CASE expression. One is referred to as simple case expression and the other is referred to as searched case expression. The SQL in your question uses the latter, i.e. searched case expression. I believe you probably need simple case expression, i.e.
select case max(dtm) over (partition by name ,id ) - current_date
when -4168 then 'Yes'
else 'No'
end as answer
from mm
select
case when current_date-max(dtm) over (partition by name ,id ) < 30 then 'yes'
else 'No' end as 'output'
from mm
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'.
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')
This is my first post, and I attempted to do a thorough search for this issue, so please accept my apologies if it has been posted elsewhere many times, but I'm wondering if anyone has encountered the following issue when attempting to remove NULLs from their result set:
case Occurrence
when NULL then '0'
else occurrence
end as Occurrence,
case Aggregate
when NULL then '0'
else Aggregate
end as Aggregate,
This didn't do anything to my NULLs; however, this did the trick:
case
when occurrence is NULL then '0'
else occurrence
end as Occurrence,
case
when aggregate is NULL then '0'
else Aggregate
end as Aggregate
Does anyone have any idea why this behaves this way? I'm using SQLServer2012.
I'm also not very versed in programming and only have less than a year SQL experience.
Thanks!
You should be using the ISNULL() or COALESCE() system function for handling nulls
something like
SELECT ISNULL(Occurrence , 0) AS Occurrence
,ISNULL(Aggregate , 0) AS Aggregate
FROM Table
OR
SELECT COALESCE(Occurrence , 0) AS Occurrence
,COALESCE(Aggregate , 0) AS Aggregate
FROM Table
The reason it didn't work in the case statement with
case Occurrence
when NULL then '0'
else occurrence
end as Occurrence,
is because it is interpreting it as
CASE
WHEN Occurrence = NULL THEN 0
ELSE Occurrence
END
Null is checked in sql server using IS NULL or IS NOT NULL if you use any other operator with null like = , <> or <, < it yields NULL hence the unexpected results.
Only for SQL Server 2012 and Later
In sql server 2012 and later versions you also have the IIF function
SELECT IIF(Occurrence IS NULL, 0, Occurrence) AS Occurrence
,IFF(Aggregate IS NULL , 0, Aggregate) AS Aggregate
FROM Table
You use simple case:
The simple CASE expression operates by comparing the first expression to the expression in each WHEN clause for equivalency. If these expressions are equivalent, the expression in the THEN clause will be returned.
Allows only an equality check.
case Occurrence
when NULL then '0'
else occurrence
end as Occurrence,
Which is executed as :
case
when occurence = NULL then '0'
else occurrence
end as Occurrence
Then expression occurence = NULL return NULL and is treated like False
Second your case use searched CASE with full condition and works fine:
case
when occurrence IS NULL then '0'
else occurrence
end as Occurrence,
So your question is about difference column IS NULL vs column = NULL
try
select 1 where null =null
select 1 where null is null
your statement looks like null equals null
select case when null is null then 1 else 0 end
select case null when null then 1 else 0 end
In your case use ISNULL this will give you the results your after
SELECT ISNULL(null,1)
tbl_LoanSummary has Sample_Number column. I have to check if Sample_Number column is not null the return 'Y' otherwise return return 'N' from below select statement.
select a.Br_Loan_No ,a.Br_LookupKey, //return IsNull(s.Sample_Number) ='N' or 'Y'
from dbo.tbl_Br a left outer join dbo.tbl_LoanSummary s
on s.Loan_no = a.Br_Loan_No order by a.Br_Loan_No
How to do this?
You can use the case expression for this...
select a.Br_Loan_No,
a.Br_LookupKey,
CASE WHEN s.Sample_Number IS NULL THEN 'N' ELSE 'Y' END AS [HasSample]
from dbo.tbl_Br a left outer join dbo.tbl_LoanSummary s
on s.Loan_no = a.Br_Loan_No order by a.Br_Loan_No
In Oracle, you could also use
select NVL(s.Sample_Number, 'N')
to return N in case of null value
(of course you still need something to have Y in case of not null.)
You'll want to use a CASE expression. It's like an embedded if-statement or switch-statement from traditional programming languages.
SELECT a.Br_Loan_No,
a.Br_LookupKey
CASE
WHEN s.Sample_Number IS NULL THEN 'N'
ELSE 'Y'
END AS sample_number_is_not_null
FROM dbo.tbl_Br a
LEFT JOIN dbo.tbl_LoanSummary s
ON s.Loan_no = a.Br_Loan_No
ORDER BY a.Br_Loan_no
Note that you are creating a computed column here, rather than selecting the raw value of an existing column. It's generally required that you give this column a name, thus the use of the AS sample_number_is_not_null.
There are two forms of the CASE expression. One lets you compare a column or value against several choices. It is like using an implicit equals:
CASE foo
WHEN 3 THEN 'foo is 3!'
WHEN 4 THEN 'foo is 4!'
ELSE 'foo is not 3 or 4'
END
The other form, in the example at the top, lets you use arbitrary expressions in each WHEN clause. It should be noted that each WHEN clause is evaluated in order and the first one to match is the one whose THEN is used as the result. If none of the WHENs match, then the result in the ELSE is used.