What is the equivalent of the below SQL Query in Oracle?
SELECT CAST(
CASE WHEN EXISTS(SELECT * FROM theTable where theColumn like 'theValue%') THEN 1
ELSE 0
END
AS BIT)
I just want an oracle query where exists is used and it returns 0 or 1 like above.
The equivalent would be:
select count(*)
from dual
where exists (SELECT * FROM theTable where theColumn like 'theValue%')
This would show the same output. Just removed the CAST and added a FROM dual as Oracle doesn't allow queries with SELECT and without FROM:
SELECT
CASE WHEN EXISTS(SELECT * FROM theTable where theColumn like 'theValue%')
THEN 1
ELSE 0
END
FROM dual ;
Tested at SQL-Fiddle
You could write it:
SELECT COUNT(*) FROM theTable WHERE theColumn LIKE 'theValue%' AND ROWNUM = 1
This will return 0-1 and the optimizer gets that the query is to be optimized for first-row access.
You could also use MAX with CASE:
SELECT MAX(
CASE
WHEN theColumn like 'theValue%' THEN 1
ELSE
0
END)
AS BIT
FROM theTable
You can use one of the following queries: (the first ones is more performant)
SELECT H.TABLE_ID, H.OTHER_FIELD,
(SELECT 'YES' FROM DUAL WHERE EXISTS (SELECT 'X' FROM TABLE_DETAIL DT
WHERE DT.TABLE_ID = H.TABLE_ID) ) WITH_DETAIL FROM TABLE_HEADER H;
SELECT H.TABLE_ID, H.OTHER_FIELD,
CASE WHEN EXISTS(SELECT * FROM IMTS.DETAIL_TABLE DT WHERE DT.TABLE_ID=H.TABLE_ID)
THEN 'Y' ELSE 'N' END WITH_DETAIL FROM HEADER_TABLE H;
SELECT H.TABLE_ID, H.OTHER_FIELD, NVL2(DT.SOME_NOTNULL_FIELD, 'YES','NO') WITH_DETAIL
FROM TABLE_HEADER H
LEFT JOIN TABLE_DETAIL DT ON DT.TABLE_ID=H.TABLE_ID AND ROWNUM<2;
Related
I have a huge query and I am wondering if it is in Oracle possible
to get the result of a case-when-statement and use it for comparison? My CASE-STATEMENT is declared in the Select-Statement and it looks like this.
SELECT........
(CASE
WHEN (Select 1 from DUAL) = 1 THEN 'TEST'
ELSE 'TEST2'
END) AS TEST;
Now I want to get the result of this case-statement and use it in the where part? Is it possible? (Sry this may be a dumb question)
If you define your CASE statement in either an inline-view or a common table expression (aka WITH clause), you can refer to it by whatever alias you give it.
For example (inline-view):
SELECT ...
FROM ( SELECT .....
(CASE
WHEN (Select 1 from DUAL) = 1 THEN 'TEST'
ELSE 'TEST2'
END) AS TEST
FROM...
) v
WHERE v.test = 'TEST2';
As a common table expression, it would be:
WITH cte AS ( SELECT........
(CASE
WHEN (Select 1 from DUAL) = 1 THEN 'TEST'
ELSE 'TEST2'
END) AS TEST
FROM ... )
SELECT ...
FROM cte
WHERE test = 'TEST2';
You can use a case statement in the where clause, for eg.:
select * from table
where table.field = (CASE
WHEN (Select 1 from DUAL) = 1 THEN 'TEST'
ELSE 'TEST2'
END)
This will compare the value returned from the case statement with the table field.
I'm trying to do something similar to this:
CASE
WHEN number IN (1,2,3) THEN 'Y' ELSE 'N' END;
Instead I want to have a query in the place of the list, like so:
CASE
WHEN number IN (SELECT num_val FROM some_table) THEN 'Y' ELSE 'N' END;
I can't seem to get this to work. Also, here is an example of the query.
SELECT number, (CASE
WHEN number IN (SELECT num_val FROM some_table) THEN 'Y' ELSE 'N' END) AS YES_NO
FROM some_other_table;
Yes, it's possible. See an example below that would do what you are intending. The difference is that it uses EXISTS instead of IN.
SELECT a.number,
(CASE WHEN EXISTS (SELECT null FROM some_table b where b.num_val = a.number)
THEN 'Y'
ELSE 'N'
END) AS YES_NO
FROM some_other_table a;
EDIT:
I confess: I like the answers given by the others better personally.
However, there will be a difference between this query and the others depending on your data.
If for a value number in the table some_other_table you can have many matching entries of num_val in the table some_table, then the other answers will return duplicate rows. This query will not.
That said, if you take the left join queries given by the others, and add a group by, then you won't get the duplicates.
I suggest using an OUTER JOIN instead of trying to use a subquery in a CASE expression:
SELECT t.NUMBER,
CASE
WHEN s.NUM_VAL IS NOT NULL THEN 'Y'
ELSE 'N'
END AS YES_NO
FROM SOME_OTHER_TABLE t
LEFT OUTER JOIN SOME_TABLE s
ON s.NUM_VAL = t.NUMBER
Best of luck.
Seems like you just need to join the tables and do a decode.
with x as
(
select 1 as num from dual
union
select 2 as num from dual
union
select 3 as num from dual
),
y as
(
select 1 as num from dual
union
select 2 as num from dual
union
select 4 as num from dual
)
select x.num, decode(y.num, null, 'N','Y') as yes_no
from x
left outer join y on (x.num = y.num)
Output:
NUM YES_NO
1 Y
2 Y
3 N
You can use subquery in case statement:
select
case dummy
when 'X' then (select 'TRUE' from dual)
else 'FALSE'
end TEST
from dual;
TEST
TRUE
select
case (select 'XXX' from dual)
when 'XXX' then 'TRUE'
else 'FALSE'
end TEST
from dual;
TEST
TRUE
I have a query that contains a WHERE clause with a CASE statement in it (See code below), somehow it doesn't seem to work.
select * FROM
details
where orgcode in
(case when orgtype='P' then
(SELECT distinct [PCode]
FROM [GPOS_Extract].[dbo].[GP8288List])
else
0 end )
How about
select * FROM details
where (orgtype <> 'P' AND orgcode = 0)
or orgcode in
(
SELECT distinct [PCode]
FROM [GPOS_Extract].[dbo].[GP8288List]
)
Or try this:
SELECT * FROM details
WHERE details.orgcode IN
( SELECT DISTINCT
(CASE WHEN details.orgtype='P'
THEN [GPOS_Extract].[dbo].[GP8288List].PCode
ELSE 0 END)
FROM [GPOS_Extract].[dbo].[GP8288List] )
I think the following is the logic that is equivalent to your attempt:
select *
FROM details
where (orgtype = 'P' and
orgcode in (SELECT distinct [PCode]
FROM [GPOS_Extract].[dbo].[GP8288List]
)
) or
((orgtype <> 'P' or orgtype is NULL) and orgcode = 0);
what about this,
select a.*,case when orgtype='P' then PCode else '0' end FROM
details a
left join [GPOS_Extract].[dbo].[GP8288List] b on a.orgcode=b.PCode
case returns a single value. You are trying to use it as though it returns a result set. What you want is:
select * FROM details d
where (orgtype = 'p'
And exists (Select *
From GPOS_Extract.dbo.GP8288List
Where PCode = d.orgcode))
or (orgtype <> 'p' And orgcode= 0)
I'm struggling to figure this one out.
What I want to do is like so:
select [fields],
((select <criteria>) return 0 if no rows returned, return 1 if any rows returned) as SubqueryResult
where a=b
Is this possible?
Please try:
select [fields],
case when (select COUNT(*) from YourTable with criteria)>0 then
1
else
0
end
as SubqueryResult
where a=b
In T-sql you can use Exists clause for the given requirement as:
select [fields],
case when exists (select <criteria> from <tablename> ) then 1
else 0
end as SubqueryResult
from <tablename>
where a=b
Also in TSQL you can do it using ISNULL() and SELECT TOP 1:
select [fields],
ISNULL((SELECT TOP 1 1 FROM YourTable WHERE <criteria> ),0)
as SubqueryResult
where a=b
Basically, what syntex would allow me to achieve the title statement?
If (select statement 1) returns 0 rows THEN (select statement 2) else (select statement 3)
So that the sql returns results from either statement 2 or 3
I've looked for a way to do this but nothing I've found so far seems to exactly address the if requirements.
IF EXISTS (SELECT field FROM table)
BEGIN
SELECT field FROM table2
END
ELSE
BEGIN
SELECT field FROM table3
END
Here you go...
IF ((select count(*) from table1)= 0)
BEGIN
Select * from table2
END
ELSE
BEGIN
SELECT * from table3
END
Sorry for the lack of feedback. Someone else in the office took an interest and came up with this:
select * from (
select *
, (SELECT Count(*)
FROM users
WHERE version_replace = 59 AND moderated = 1) AS Counter
FROM users WHERE version_replace = 59 AND moderated in (0,1)
) AS y
where Counter = 0 and Moderated = 0
or Counter > 0 and Moderated = 1
ORDER By ID DESC
Which does what I need.