I've got table with few numbers inside (or even empty): #states table (value int)
And I need to make SELECT from another table with WHERE clause by definite column.
This column's values must match one of #states numbers or if #states is empty then accept all values (like there is no WHERE condition for this column).
So I tried something like this:
select *
from dbo.tbl_docs docs
where
docs.doc_state in(iif(exists(select 1 from #states), (select value from #states), docs.doc_state))
Unfortunately iif() can't return subquery resulting dataset. I tried different variations with iif() and CASE but it wasn't successful. How to make this condition?
select *
from dbo.tbl_docs docs
where
(
(select count(*) from #states) > 0
AND
docs.doc_state in(select value from #states)
)
OR
(
(select count(*) from #states)=0
AND 1=1
)
Wouldn't a left join do?
declare #statesCount int;
select #statesCount = count(1) from #states;
select
docs.*
from dbo.tbl_docs docs
left join #states s on docs.doc_state = s.value
where s.value is not null or #statesCount = 0;
In general, whenever your query contains sub-queries, you should stop for five minutes, and think hard about whether you really need a sub-query at all.
And if you've got a server capable of doing that, in many cases it might be better to preprocess the input parameters first, or perhaps use constructs such as MS SQL's with.
select *
from dbo.tbl_docs docs
where exists (select 1 from #states where value = doc_state)
or not exists (select 1 from #state)
Related
So I'm creating a query for a report that could have several optional filters. I've only included client and station here to keep it simple. Each of these options could be an include or an exclude and could contain NULL, 1, or multiple values. So I split the varchar into a table before joining it to the query.
This test takes about 15 minutes to execute, which... just won't do :p Is there a better way? We have similar queries written with dynamic sql, and I was trying to avoid that, but maybe there's no way around it for this?
DECLARE
#ClientsInc VARCHAR(10) = 'ABCD, EFGH',
#ClientsExc VARCHAR(10) = NULL,
#StationsInc VARCHAR(10) = NULL,
#StationsExc VARCHAR(10) = 'SomeStation'
SELECT *
INTO #ClientsInc
FROM dbo.StringSplit(#ClientsInc, ',')
SELECT *
INTO #ClientsExc
FROM dbo.StringSplit(#ClientsExc, ',')
SELECT *
INTO #StationsInc
FROM dbo.StringSplit(#StationsInc, ',')
SELECT *
INTO #StationsExc
FROM dbo.StringSplit(#StationsExc, ',')
SELECT [some stuff]
FROM media_order mo
LEFT JOIN #ClientsInc cInc WITH(NOLOCK) ON cInc.Value = mo.client_code
LEFT JOIN #ClientsExc cExc WITH(NOLOCK) ON cExc.Value = mo.client_code
LEFT JOIN #StationsInc sInc WITH(NOLOCK) ON sInc.Value = mo.station_name
LEFT JOIN #StationsExc sExc WITH(NOLOCK) ON sExc.Value = mo.station_name
WHERE ((#ClientsInc IS NOT NULL AND cInc.Value IS NOT NULL)
OR (#ClientsExc IS NOT NULL AND cExc.Value IS NULL)
)
AND ((#StationsInc IS NOT NULL AND sInc.Value IS NOT NULL)
OR (#StationsExc IS NOT NULL AND sExc.Value IS NULL)
)
First of all, I always tend to mention Erland Sommarskog's Dynamic Search Conditions in such cases.
However, you already seem to be aware of the two options: one is dynamic SQL. The other is usually the old trick and (#var is null or #var=respective_column). This trick, however, works only for one value per variable.
Your solution indeed seems to work for multiple values. But in my opinion, you are trying too hard to avoid dynamic sql. Your requirements are complex enough to guarantee it. And remember, usually, dynamic sql is harder for you to code, but easier for the server in complex cases - and this one certainly is. Making a performance guess is always risky, but I would guess an improvement in this case.
I would use exists and not exists:
select ...
from media_order mo
where
(
#ClientsInc is null
or exists (
select 1
from string_split(#ClientsInc, ',')
where value = mo.client_code
)
)
and not exist (
select 1
from string_split(#ClientsExc, ',')
where value = mo.client_code
)
and (
#StationsInc is null
or exists (
select 1
from string_split(#StationsInc, ',')
where value = mo.station_name
)
)
and not exist (
select 1
from string_split(#StationsExc, ',')
where value = mo.station_name
)
Notes:
I used buil-in function string_split() rather than the custom splitter that you seem to be using. It is available in SQL Server 2016 and higher, and returns a single column called value. You can change that back to your customer function if you are running an earlier version
as I understand the logic you want, "include" parameters need to be checked for nullness before using exists, while it is unnecessary for "exclude" variables
I want use the SQL Server IN operator and also set a variable to a column value. Is this possible?
My code is like this:
DECLARE #SubkindId as tinyint;
SELECT NAME FROM SampleTable001 WHERE
Id in (SELECT Id, #SubkindId = Subkind FROM SampleTable002)
ORDER BY Name;
My issue is: I want to set the #SubkindId variable in the inner select statement.
Can It Be Done?
In SQL Server you can't SELECT a result set and SET variables in the same statement (though you can in MySQL). Sorry. But there may be another way to get what you want. Unfortunately, what you want is not completely clear.
Assuming you want to do a SELECT and at the same time return another value into a variable, you have to handle the issue that your query can return multiple rows, so in that case, which one would you want to return into #SubkindId?
Now, I may have misunderstood, and instead of trying to pull the column value into the variable, you instead want to pull only the row where the SubkindId matches the value already in the variable (though you didn't show assigning a value to it first, so this seems less likely).
Please confirm which is the case and answer the above questions, and I can help you more.
In the meantime, I'll try to give you answers for both scenarios.
First, let me mention that I recommend against using the IN() syntax with a subquery returning a list of IDs. It is poor practice in my opinion because it usually demonstrates that the person doesn't really know how to JOIN properly, and as soon as the query gets a little complicated, not only that person but even the best professional SQL Server query writer can get lost (... WHERE x IN (SELECT ... WHERE y IN (SELECT ... WHERE z NOT IN (...))) which soon leads to a serious case of what!?!?!?!. Just use JOINs, and if required, semi-joins (introduced with an EXISTS clause).
Query and Return a Value
If what you really wanted was to get access to the values that the SELECT statement found while doing its join, it might look something like this:
DECLARE #KindsAndSubkinds TABLE (
Name varchar(100),
SubkindId tinyint
);
INSERT #KindsAndSubkinds
SELECT
T1.Name,
T2.SubkindId
FROM
dbo.SampleTable001 T1
INNER JOIN dbo.SampleTable002 T2
ON T1.Id = T2.Id
SELECT DISTINCT Name
FROM #KindsAndSubkinds
ORDER BY Name;
-- Now you can something with the `SubkindId`s in the #KindsAndSubkinds table variable.
Just Query
If you really were just trying to query rather than return a value, this is what I would recommend:
DECLARE #SubkindId as tinyint;
SET #SubkindId = 5;
SELECT
T1.Name
FROM
dbo.SampleTable001 T1
INNER JOIN dbo.SampleTable002 T2
ON T1.Id = T2.Id
WHERE
T2.Subkind = #SubkindId
ORDER BY
T1.Name;
If there are multiple rows in SampleTable002 but you don't want them in the result set, then:
SELECT
T1.Name
FROM
dbo.SampleTable001 T1
WHERE
EXISTS (
-- This semi-join requires at least one row to exist
-- but doesn't increase the row count
SELECT *
FROM dbo.SampleTable002 T2
WHERE
T1.Id = T2.Id
AND T2.Subkind = #SubkindId
)
ORDER BY
T1.Name;
I hope this helps.
Do it like this:
DECLARE #SubkindId as tinyint
SELECT [NAME]
FROM SampleTable001
WHERE Id in (SELECT Id
from SampleTable002
WHERE Subkind=#SubkindId)
order by [Name]
or by using JOIN
DECLARE #SubkindId as tinyint
SELECT [NAME]
FROM SampleTable001 a
INNER JOIN SampleTable002 b
ON a.id = b.id
WHERE b.Subkind=#SubkindId
order by [Name]
Writing a stored procedure that will have multiple input parameters. The parameters may not always have values and could be empty. But since the possibility exists that each parameter may contain values I have to include the criterion that utilizing those parameters in the query.
My query looks something like this:
SELECT DISTINCT COUNT(*) AS SRM
FROM table p
WHERE p.gender IN (SELECT * FROM Fn_SplitParms(#gender)) AND
p.ethnicity IN (SELECT * FROM Fn_SplitParms(#race)) AND
p.marital_status IN (SELECT * FROM Fn_SplitParms(#maritalstatus))
So my problem is if #gender is empty(' ') the query will return data where gender field is empty when I really want to just ignore p.gender all together. I don't want to have to accomplish this task using IF/ELSE conditional statements because they would be too numerous.
Is there any way to use CASE with IN for this scenario? OR
Is there other logic that I'm just not comprehending that will solve this?
Having trouble finding something that works well...
Thanks!
Use or:
SELECT DISTINCT COUNT(*) AS SRM
FROM table p
WHERE
(p.gender IN (SELECT * FROM Fn_SplitParms(#gender)) OR #gender = '')
AND (p.ethnicity IN (SELECT * FROM Fn_SplitParms(#race)) OR #race = '')
AND (p.marital_status IN (SELECT * FROM Fn_SplitParms(#maritalstatus)) OR #maritalstatus = '')
You might also want to consider table-valued parameters (if using SQL Server 2008 and up) - these can sometimes make the code simpler, since they are treated as tables (which in your case, may be empty) and you can join - plus no awkward split function required.
I have the following SQL query:
Declare #Total_SysDown as int,
#Login_SysDown as int
Set #Total_SysDown = (SELECT SCHED_SYS_DOWN FROM AGT_SC AS S)
Set #Login_SysDown = (SELECT SYS_DOWN FROM AGT_AC AS A)
Insert Into dbo.DATA(DATE,ID,LNAME,FNAME,Total_SysDown,Login_SysDown)
Select C.DATE,C.ID,E.Last_Name,E.First_Name,#Total_SysDown #Login_SysDown
From dbo.AGT as C Inner Join dbo.EMP as E ON C.ID = E.ID
Group by C.ID,C.DATE,E.Last_Name,E.First_Name
This or just the variables with the Select statement gives me an error of Subquery returned than 1 value. From what I understand, this means that I should be inserting one record at a time, but I am unsure how to do this. Is there a while statement I should be putting in, or are my variables actually hindering me in the first place?
At least one of the queries:
(SELECT SCHED_SYS_DOWN FROM AGT_SC AS S)
(SELECT SYS_DOWN FROM AGT_AC AS A)
returns more than 1 row, so you cannot assign it to a scalar variable.
As a temporary solution you can do SELECT TOP 1 to make sure each query returns at most one row.
I don't think the problem is with your INSERT statement at all.
Your problem is in the SET Statements. The SELECT SCHED_SYS_DOWN FROM AGT_SC AS S statement or the other statement is returning more than one value.
When you use SET you are assigning ONE value to the variable. Your SELECT is returning multiple values. Change your query to return only one row.
You're receiving this error because your subqueries return more than one record:
Set #Total_SysDown = (SELECT SCHED_SYS_DOWN FROM AGT_SC AS S)
Set #Login_SysDown = (SELECT SYS_DOWN FROM AGT_AC AS A)
To use variables here, you will need to ensure that only one record is returned from the query, either by using a WHERE clause, TOP 1, or something else. I can't tell for sure by your example, but it sounds like you should be joining those tables to your SELECT query.
SELECT ...
FROM dbo.AGT agt
INNER JOIN AGT_SC sc
ON sc.<joining column> = <joining table>.<joining column>
INNER JOIN AGT_AC ac
ON ac.<joining column> = <joining table>.<joining column>
This is probably a really simple question, but I don't write stored procedures often and I'm a bit mystified...
After doing various stuff, the concluding bit of the SP ends by returning counts or sums from several different tables. The obvious approach is:
select SUM(ThisCol) as ThisResult from...
select SUM(ThatCol) as ThatResult from...
select count(DISTINCT OtherCol) as OtherResult from...
Of course, this creates multiple recordsets - one for each select plus one containing zero. This is a bit silly since each recordset contains exactly one value. I would much prefer to return a single recordset with multiple columns: ThisResult, ThatResult and OtherResult.
Is that possible?
You can use variables
DECLARE #thisResult INT
DECLARE #thatResult INT
DECLARE #otherResult INT
select #thisResult = SUM(ThisCol) as ThisResult from...
select #thatResult = SUM(ThatCol) as ThatResult from...
select #otherResult = count(OtherCol) as OtherResult from...
SELECT #thisResult AS 'thisResult', #thatResult AS 'thatResult', #otherResult AS 'otherResult'
SELECT T1.ThisResult, T2.ThatResult, T3.OtherResult
FROM (select SUM(ThisCol) as ThisResult from...) T1,
(select SUM(ThatCol) as ThatResult from...) T2,
(select count(DISTINCT OtherCol) as OtherResult from...) T3
Because each table contains only 1column & 1 value, you do a cross join of all 3 and put each value in a column in the result table.
If you're using SQL Server, you can select these quantities again as your last statement.
Select ThisResult, ThatResult, OtherResult
You don't have to specify a table