I have an SQL query joined on multiple tables (all INNER JOINS).
The below is an example of the query I am trying to run (the ? is to illustrate the position in which I presume the answer to my question will be rectified).
Case
(
SELECT Count(ID)
FROM CPD_Candidates cpdCan
WHERE
cpdCan.CandidateID = can.CandidateID
AND
(
cpdCan.DateEnded >= GETDATE()
OR
coalesce(cpdCan.DateEnded, '') = N'1-Jan-1900'
)
AND
cpdCan.Deleted <> 1
)
When ? > 0 then 'Bigger' else 'Equal or Smaller' End
)
The idea with the above is that instead of the ? the actual value I want to compare against would be Count(ID), if it's greater than 0 I want it to SELECT 'Bigger', otherwise it should SELECT 'Equal or Smaller'. So a more-accurate depiction of what I wish to run would be the below.
Case
(
SELECT Count(ID)
FROM CPD_Candidates cpdCan
WHERE
cpdCan.CandidateID = can.CandidateID
AND
(
cpdCan.DateEnded >= GETDATE()
OR
coalesce(cpdCan.DateEnded, '') = N'1-Jan-1900'
)
AND
cpdCan.Deleted <> 1
)
When
Count(cpdCan.ID) > 0 then 'Bigger' else 'Equal or Smaller' End
)
Of course there is a syntax error above but I am enquiring as to whether it is possible to compare like in the above SQL query structure but replacing Count(cpdCan.ID) > 0 with some other means to achieve that value & logic?
If this is un-achievable in SQL Server 2016 what other means would be a better solution to this XY?
I think that you mean:
case when
(
SELECT Count(ID)
FROM CPD_Candidates cpdCan
WHERE
cpdCan.CandidateID = can.CandidateID
AND (cpdCan.DateEnded >= GETDATE() OR coalesce(cpdCan.DateEnded, '') = N'1-Jan-1900')
AND cpdCan.Deleted <> 1
) > 0
then 'Bigger'
else 'Equal or Smaller'
End
Related
I am having some trouble with the syntax when I am trying to use the below query in SQL Server. I wanted to show WHERE clause based on condition.
This is my code:
DECLARE #isActual = 0
SELECT
SolverRunId, PointId, TimeStampUtc, Value,
UnitOfMeasure, Reliability
FROM
(SELECT
bt.SolverRunId, bt.PointId, bt.TimeStampUtc,
bt.Value, bt.UnitOfMeasure, bt.Reliability
FROM
cte bt
WHERE
bt.TimeStampUtc = bt.TargetTimeUtc
UNION ALL
SELECT
a.SolverRunId, a.PointId, a.TimeStampUtc, a.Value,
a.UnitOfMeasure, a.Reliability
FROM
cte a
WHERE
-- I tried using this case but it is syntactically incorrect
CASE
WHEN #isActual = 0 THEN a.TimeStamUtc > #endDateUtc
ELSE a.TimestampUtc <= #endDateUtc
END
-- instead of this. I wanted to have conditional where based on #isActual value from 0 to 1
a.TimeStampUtc > #endDateUtc
AND a.SolverRunId = #maxRun) x
ORDER BY
SolverRunId, PointId, TimeStampUtc;
I wanted to have the where condition to be evaluated based on #isActual set to true or false
As mentioned in the comments, don't use a CASE in the WHERE just use proper boolean logic with AND and OR clauses. In your question your variable #isActual is also missing a data type, so I have assumed it is a bit:
DECLARE #isActual bit = 0;
SELECT SolverRunId,
PointId,
TimeStampUtc,
Value,
UnitOfMeasure,
Reliability
FROM (SELECT bt.SolverRunId,
bt.PointId,
bt.TimeStampUtc,
bt.Value,
bt.UnitOfMeasure,
bt.Reliability
FROM cte bt
WHERE bt.TimeStampUtc = bt.TargetTimeUtc
UNION ALL
SELECT a.SolverRunId,
a.PointId,
a.TimeStampUtc,
a.Value,
a.UnitOfMeasure,
a.Reliability
FROM cte a
WHERE a.TimeStampUtc > #endDateUtc
AND a.SolverRunId = #maxRun
AND ((#isActual = 0 AND a.TimeStamUtc > #endDateUtc)
OR (#isActual = 1 AND a.TimestampUtc <= #endDateUtc))) x
ORDER BY SolverRunId,
PointId,
TimeStampUtc;
You may also want experiment with adding RECOMPILE to the OPTION clause of the above, as the query plan requirements for when #isActual has a value of 1 or 0 could be quite different.
I am having problem in part of my code anyway to do this
Only one expression can be specified in the select list when the subquery is not introduced with EXISTS. The update part is working but how to use insert into to calculate if a condition is not meant it will insert.
IF
/* CHECKLIST TO UPDATE*/
(NOT EXISTS
(SELECT *
FROM ENERGY.D_ENERGY_REFERENCE D_ENERGY_REFERENCE
,ENERGY.D_CHECK_LIST D_CHECK_LIST
WHERE D_ENERGY_REFERENCE.ID = D_CHECK_LIST.ID
AND D_ENERGY_REFERENCE.REFERENCE = 19051
)
)
BEGIN
INSERT INTO DB.D_ENERGY_REFERENCE(ID, REFERENCE_NO, REFERENCE,VALUE_INTEGER)
(SELECT ID,
(SELECT ISNULL(MAX(REFERENCE_NO), 0) + 1 FROM DB.D_ENERGY_REFERENCE),
19051, (SELECT D_CHECK_LIST.ID,
CASE
WHEN CAST(COUNT(CASE WHEN D_CHECK_LIST.EVALUATION NOT IN (0,1) THEN EVALUATION ELSE NULL END) AS FLOAT) = 0 THEN NULL
ELSE
(
CAST(COUNT(CASE WHEN D_CHECK_LIST.EVALUATION IN (2, 3, 50001, 50003, 50004, 50005, 50006, 50020, 50027, 50028) THEN EVALUATION ELSE NULL END) AS FLOAT)
/
CAST(COUNT(CASE WHEN D_CHECK_LIST.EVALUATION NOT IN (0,1) THEN EVALUATION ELSE NULL END) AS FLOAT)
) * 100
END FROM DB.D_CHECK_LIST
GROUP BY D_CHECK_LIST.ID)
FROM DB.D_ENERGY_REFERENCE D_ENERGY_REFERENCE
WHERE D_ENERGY_REFERENCE.ID = ID AND D_ENERGY_REFERENCE.REFERENCE = 19051
GROUP BY D_ENERGY_REFERENCE.ID
)
END
Can you please check this following part in the sub query of your script-
.......
19051,
(
SELECT
D_CHECK_LIST.ID, -- This is the column 1
CASE
WHEN -- Here you are generating column 2 in the sub query
......
)
Here you are selecting 2 column - one is "D_CHECK_LIST.ID" and other one is generation through CASE WHEN statement. I think you should SELECT any 1 column from those 2 column. If both are required, you can use separate Sub query for that.
The ERROR code "Only one expression can be specified in the select list when the subquery is not introduced with EXISTS" is self explanatory that you can not implement a Sub Query with more than 1 column selected unless the Sub Query is using inside EXISTS method.
My query is basic and look like this :
SELECT ID FROM Table WHERE CRIT1='a' AND CRIT2='b' AND CRIT3='c'
However it sometimes return no value. This is normal because there is no match in the table.
To help my users to find which criteria is too restrictive, I would like to find another query which tell me if it is because of clause CRIT1, CRIT2 or CRIT3 that I have no answer.
Currently, I've done it this way (using pseudo code) :
If ( SELECT ID FROM Table WHERE CRIT1='a' returns EOF )
Then WrongCriteria="CRIT1"
Elseif ( SELECT ID FROM Table WHERE CRIT1='a' AND CRIT2='b' returns EOF )
Then WrongCriteria="CRIT2"
Elseif ( SELECT ID FROM Table WHERE CRIT1='a' AND CRIT2='b' AND CRIT3='c' returns EOF )
Then WrongCriteria="CRIT3"
It works ... but there are several queries and each of them is very slow due to the poor network response time.
My question is thus : It is possible to do the above pseudo-code in one single SQL query?
You can combine three queries into one by using SUM on a conditional:
SELECT
SUM(CASE WHEN CRIT1='a' THEN 1 ELSE 0 END) as CRIT1
, SUM(CASE WHEN CRIT1='a' AND CRIT2='b' THEN 1 ELSE 0 END) as CRIT2
, SUM(CASE WHEN CRIT1='a' AND CRIT2='b' AND CRIT3='c' THEN 1 ELSE 0 END) as CRIT3
FROM MyTable
Zero in a column corresponds to the criterion being to restrictive.
Note that this is only a different implementation of your three queries, which "prioritizes" the criteria in a specific way (crit1 then crit2 then crit3). In theory, with three criteria you want to test all individual ones, plus three combinations of pairs, i.e get six counts for these conditions:
CRIT1='a'
CRIT2='b'
CRIT3='c'
CRIT1='a' && CRIT2='b'
CRIT1='a' && CRIT3='c'
CRIT2='b' && CRIT3='c'
The above six counts would give you a full picture of which criteria are too restrictive.
Yes it's possible to do this check in a single query using 'OR' operator.
I'm assuming it's only one condition which can be wrong at a time:
SELECT CASE WHEN CRIT1 <> 'a' THEN 'CRIT1'
WHEN CRIT2 <> 'b' THEN 'CRIT2'
WHEN CRIT3 <> 'c' THEN 'CRIT3' END AS WrongCriteria
FROM Table WHERE CRIT1<>'a' OR CRIT2<>'b' OR CRIT3<>'c'
To show all combinations of restrictions:
SELECT
COALESCE( 'Conditions:'
+ NULLIF(
( CASE WHEN CRIT1 <> 'a' THEN ' CRIT1' ELSE '' END )
+ ( CASE WHEN CRIT2 <> 'b' THEN ' CRIT2' ELSE '' END )
+ ( CASE WHEN CRIT3 <> 'c' THEN ' CRIT3' ELSE '' END ),
'' ),
'None' ) AS Restrictions
FROM MyTable
I was wondering if something like this was possible in SQL :
select (
(select count(*) from T) = (select count(*) from T t where t.something = thing)
)
This is probably very far from the actual SQL if it is possible, I don't write database requests so often.
How could I get the result of my comparison with a single request ? Basically, if I had no time, I would just make two requests and compare the results in Java (boooooo !! I know).
Although your query should work, the following is probably faster because only a single query is needed
select total_count = thing_count
from (
select count(*) as total_count,
sum(case when something = 42 then 1 end) as thing_count
from t
) t
The above is ANSI SQL and should work in any DBMS supporting a real boolean type. In Oracle you would need to use an expression in the outer select:
select case when total_count = thing_count then 1 else 0 end
from (
select count(*) as total_count,
sum(case when something = 42 then 1 end) as thing_count
from t
) t
I would write your query like this:
SELECT (CASE WHEN (select count(*) from T) = (select count(*) from T t where t.something = thing) THEN 1 ELSE 0 END)
However, if the first T is the same as the second T then what you actually want to check is if there are any records where t.something <> thing .. right ?
In that case you could simply do :
SELECT (CASE WHEN EXISTS (select * from T t where t.something != thing) THEN 1 ELSE 0 END)
SELECT MyTable.Name,
(
SELECT CASE WHEN ISNULL(SUM(TotalDays), 0) <= 0 THEN 0
ELSE SUM(TotalDays)
END AS Total
FROM Application AS Applications
WHERE (ID = MyTable.id)
) - MIN(Assignments) AS Excesses
FROM MyTable
The above TSQL statement is a subquery in a main query. When i run it, if TotalDays is NULL or <=0, then Total is set to 0 (zero).
What i would like to do here is to set the result of the whole query(Excesses) to 0. I want (Excesses) which is the result of Total - Min(Assignments) to be set to 0 if its NULL or <=0.
I want the CASE WHEN to apply to the whole query but am struggling to get it right.
SELECT
MyTable.Name,
CASE WHEN
0 < (SELECT SUM(TotalDays) FROM Application WHERE ID = MyTable.id) - MIN(Assignments)
THEN
(SELECT SUM(TotalDays) FROM Application WHERE ID = MyTable.id) - MIN(Assignments)
ELSE
0
END AS [Excesses]
FROM
MyTable
Note: MS SQL Server won't exexute the two correlated-sub-queries independantly, it will infact recognise that they are the same and re-use the results.
Alternative:
SELECT
MyTable.Name,
CASE WHEN
0 < SUM([application].TotalDays) - MIN([MyTable].Assignments)
THEN
SUM([application].TotalDays) - MIN([MyTable].Assignments)
ELSE
0 -- If either aggregate is NULL, 0 will still be returned
END AS [Excesses]
FROM
MyTable
LEFT JOIN
Application
ON [application].ID = [MyTable].id
SELECT MyTable.Name, CASE WHEN ISNULL(SUM(TotalDays), 0) <= 0 THEN 0 ELSE SUM(TotalDays) END AS Total
FROM Application AS Applications
JOIN MyTable
ON Applications.id = mytable.id
GROUP BY
MyTable.id, MyTable.name
HAVING CASE WHEN ISNULL(SUM(TotalDays), 0) <= 0 THEN 0 ELSE SUM(TotalDays) END > 0