I have a certain validation on my SQL Query.
WHERE USER_ACTIVE = 'Y'
But I want this validation to appear only when my FLAG is set to TRUE.
like, when FLAG is set to true, check user_active column.
when FLAG is false, then proceed without validation.
tried below but i think its not possible
WHERE CASE WHEN FLAG = 'TRUE' then USER_ACTIVE = 'Y' else ' ' END
Any reco?
Thanks IA!
The logic is something like this:
WHERE USER_ACTIVE = 'Y' OR #FLAG <> 'TRUE'
You can also use CASE with WHERE. Just to point out, CASE statement only assigns values based on conditions. So, you need to make comparisons after the assignation is done. Try something like this:
WHERE (CASE WHEN FLAG = 'TRUE' then USER_ACTIVE else ' ' END) = 'Y'
Related
I'm creating a yes/no flag for SQL data and I have something similar to:
'''
CASE WHEN col_name IS NULL OR col_name = 0 THEN "N"
ELSE "Y"
END AS col_name_flag
'''
Is there any way to be more concise so I don't have to have the column name written out twice? Many of the column names are very long so I was wondering if there would be a way to make it more visually pleasing.
Probably the simplest method is to reverse the comparison:
(CASE WHEN col_name <> 0 THEN 'Y' ELSE 'N' END) AS col_name_flag
You could also use:
CASE IsNull(col_name,0) =0 THEN 'N' ELSE 'Y' END as col_name_flag
But I would go with Gordon's answer for performance...
Hi I'm trying to put on a validation on my where clause. But this validation needs only to exist when a certain condition is met else i dont need this validation.
I tried but i am not getting my expected output. Maybe I missed something? Please help
WHERE (CASE
WHEN 1 = (SELECT DECODE (PARAMETER_VALUE, 'FALSE', 1, 2)
FROM TABLE_A
WHERE PARAMETER_NAME = 'STUDENT_STATUS')
THEN
INVALID_STAT
ELSE
' '
END) = 'Y'
What about replacing the last ' ' to 'Y'. So when the query returns a result it converts to
WHERE INVALID_STAT = 'Y'
And when the query doesn't return any result it converts to -
WHERE 'Y' = 'Y'
Thus ignoring the condition.
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'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.
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 ''