I have a piece of SQL that takes a parameter, assesses the contents of the parameter and depending on the contents applies different UDF to the input parameter.
the code goes something like this:
declare #order varchar(50) = 's12345..s12347'
if isnull( CHARINDEX('.',#order),0) >0
begin
select n as order_no into #temp
FROM F_GetAllNBetween(#order)
end
else if ( isnull( CHARINDEX(',',#order),0) >0 )
begin
select [value] as order_no into #temp2
FROM dbo.F_SplitList(#order,',')
end
if OBJECT_ID('tempdb..#temp') is not null
select * from #temp where order_no <>''
if OBJECT_ID('tempdb..#temp2') is not null
select * from #temp2 where order_no <>''
what I want to do is, get the output from the above union into another temp table and use it in the where clause of the rest of the code.
I cannot use union as it errors saying a select is expected.
I cannot use cte as I cannot use the check to see if the temp tables are empty
I cannot ignore checking for empty temp tables else it errors saying object does not exist ( if statement only creates one of the two temp tables)
I cannot figure out how to get the output to a different temp table. Any ideas suggestions or better way of doing the same please?
As mentioned in my comment, you can simplify your current code to achieve what you want with a UNION and WHERE clauses to replace the IF statements. e.g.
SELECT order_no
--INTO #someTempTable -- if needed
FROM (
SELECT order_no = n
FROM dbo.F_GetAllNBetween(#order)
WHERE CHARINDEX('.', #order) > 0
UNION ALL
SELECT value
FROM dbo.F_SplitList(#order,',')
WHERE CHARINDEX(',', #order) > 0
) AS T
WHERE order_no <> '';
Related
If I run something like this:
select [agent_name], [agent_department], count(*) as [row_count]
from [table_name]
where [agent_name] IS NOT NULL
group by [agent_name] [agent_department];
Nothing will come back if there are no records to return (i.e. the table is empty).
If I run this
select count(*) as [row_count]
from [table_name]
where [agent_name] IS NOT NULL
I will get a row_count of 0.
Is there a way I can run the first query, and, if there are no records, have it return row_count 0?
This might not be very beautiful, but it should bring back what you want:
I start with a tiny mockup:
DECLARE #mockup TABLE(agent_name varchar(100),agent_department varchar(100));
--The query will read your SELECT within a CTE.
WITH cte AS
(
select [agent_name], [agent_department], count(*) as [row_count]
from #mockup
where [agent_name] IS NOT NULL
group by [agent_name],[agent_department]
)
SELECT agent_name,agent_department,row_count FROM cte
UNION ALL SELECT NULL,NULL,0 WHERE (SELECT COUNT(*) FROM cte)=0;
The result
agent_name agent_department row_count
NULL NULL 0
You see, that the resultset is called as is, while there is a UNION ALL SELECT query, which will deliver only in cases, where the cte has no rows.
Now we insert some data to the table
INSERT INTO #mockup VALUES('blah','blub');
WITH cte AS
(
select [agent_name], [agent_department], count(*) as [row_count]
from #mockup
where [agent_name] IS NOT NULL
group by [agent_name],[agent_department]
)
SELECT agent_name,agent_department,row_count FROM cte
UNION ALL SELECT NULL,NULL,0 WHERE (SELECT COUNT(*) FROM cte)=0;
the new result is now
agent_name agent_department row_count
blah blub 1
I have a straight forward SQL query that I am working with and trying to figure out the best way to approach the where clause.
Essentially, there are two temp tables created and if there is data in the XML string passed to the stored procedure, those tables are populated.
My where clause needs to check these temp tables for data, and if there is no data, it ignores them like they are not there and fetches all data.
-- Create temp tables to hold our XML filter criteria
DECLARE #users AS TABLE (QID VARCHAR(10))
DECLARE #dls AS TABLE (dlName VARCHAR(50))
-- Insert our XML filters
IF #xml.exist('/root/data/users') > 0
BEGIN
INSERT INTO #users( QID )
SELECT ParamValues.x1.value('QID[1]', 'varchar(10)')
FROM #xml.nodes('/root/data/users/user') AS ParamValues(x1)
END
IF #xml.exist('/root/data/dls') > 0
BEGIN
INSERT INTO #dls( dlName )
SELECT ParamValues.x1.value('dlName[1]', 'varchar(50)')
FROM #xml.nodes('/root/data/dld/dl') AS ParamValues(x1)
END
-- Fetch our document details based on the XML provided
SELECT d.documentID ,
d.sopID ,
d.documentName ,
d.folderLocation ,
d.userGroup ,
d.notes
FROM dbo.Documents AS d
LEFT JOIN dbo.DocumentContacts AS dc
ON dc.documentID = d.documentID
LEFT JOIN dbo.DocumentContactsDLs AS dl
ON dl.documentID = d.documentID
-- How can I make these two logic checks work only if there is data, otherwise, include everything.
WHERE dc.QID IN (SELECT QID FROM #users)
AND dl.DL IN (SELECT dlName FROM #dls)
FOR XML PATH ('data'), ELEMENTS, TYPE, ROOT('root');
In the query above, I am trying to used the data in the temp tables only if there is data in them, otherwise, it needs to act like that where statement isn't there for that specific value and include records regardless.
Example: If only #users had data, it would ignore AND dl.DL IN (SELECT dlName FROM #dls) and get everything, regardless of what was in the DL column on those joined records.
Use NOT EXISTS to check the existence of any record in variable table. Here is one way
WHERE ( dc.QID IN (SELECT QID FROM #users)
OR NOT EXISTS (SELECT 1 FROM #users) )
AND ( dl.DL IN (SELECT dlName FROM #dls)
OR NOT EXISTS (SELECT 1 FROM #dls) )
Try this. But please note that I did not get a chance to test it properly and I believe that you want to check the values in #users first and if there is no record existing in that table, then you want to check with the entries in #dls. Also if there are no entries in both of these tables, then you want to skip both the tables.
DECLARE #fl bit = 0
SELECT #fl = CASE WHEN EXISTS (SELECT 1 FROM #users) THEN
1
WHEN EXISTS (SELECT 1 FROM #dls) THEN
2
ELSE
0
END
WHERE ( (dc.QID IN (SELECT QID FROM #users) AND #fl = 1)
OR
(dl.DL IN (SELECT dlName FROM #dls) AND #fl = 2)
OR (1=1 AND #fl = 0)
)
The Situation
We have an application where we store machine settings in a SQL table. When the user changes a parameter of the machine, we create a "revision", that means we insert a row into a table. This table has about 200 columns.
In our application, the user can take a look on each revision.
The Problem
We want to highlight the parameters that have changed since the last revision.
The Question
Is there an SQL-only way to get the column names of the differences between two rows?
An Example
ID | p_x | p_y | p_z
--------------------
11 | xxx | yyy | zzz
12 | xxy | yyy | zzy
The query should return p_x and p_z.
EDIT
The table has 200 columns, not rows...
MY WAY OUT
My intention was to find a "one-line-SQL-statement" for this problem.
I see in the answers below, it's kind a bigger thing in SQL.
As there is no short, SQL-included solution for this problem, solving it in the backend of our software (c#) is of course much easier!
But as this is not a real "answer" to my question, I don't mark it as answered.
Thanks for the help.
You say:
We want to highlight the parameters that have changed since the last revision.
This implies that you want the display (or report) to make the parameters that changed stand out.
If you're going to show all the parameters anyway, it would be a lot easier to do this programmatically in the front end. It would be a much simpler problem in a programming language. Unfortunately, not knowing what your front end is, I can't give you particular recommendations.
If you really can't do it in the front end but have to receive this information in a query from the database (you did say "SQL-only"), you need to specify the format you'd like the data in. A single-column list of the columns that changed between the two records? A list of columns with a flag indicating which columns did or didn't change?
But here's one way that would work, though in the process it converts all your fields to nvarchars before it does its comparison:
Use the technique described here (disclaimer: that's my blog) to transform your records into ID-name-value pairs.
Join the resulting data set to itself on ID, so that you can compare the values and print those that have changed:
with A as (
-- We're going to return the product ID, plus an XML version of the
-- entire record.
select ID
, (
Select *
from myTable
where ID = pp.ID
for xml auto, type) as X
from myTable pp )
, B as (
-- We're going to run an Xml query against the XML field, and transform it
-- into a series of name-value pairs. But X2 will still be a single XML
-- field, associated with this ID.
select Id
, X.query(
'for $f in myTable/#*
return
<data name="{ local-name($f) }" value="{ data($f) }" />
')
as X2 from A
)
, C as (
-- We're going to run the Nodes function against the X2 field, splitting
-- our list of "data" elements into individual nodes. We will then use
-- the Value function to extract the name and value.
select B.ID as ID
, norm.data.value('#name', 'nvarchar(max)') as Name
, norm.data.value('#value', 'nvarchar(max)') as Value
from B cross apply B.X2.nodes('/myTable') as norm(data))
-- Select our results.
select *
from ( select * from C where ID = 123) C1
full outer join ( select * from C where ID = 345) C2
on C1.Name = c2.Name
where c1.Value <> c2.Value
or not (c1.Value is null and c2.Value is null)
You can use unpivot and pivot. The key is to transpose data so that you can use where [11] != [12].
WITH CTE AS (
SELECT *
FROM
(
SELECT ID, colName, val
FROM tblName
UNPIVOT
(
val
FOR colName IN ([p_x],[p_y],[p_z])
) unpiv
) src
PIVOT
(
MAX(val)
FOR ID IN ([11], [12])
) piv
)
SELECT colName
--SELECT *
FROM CTE WHERE [11] != [12]
If there are only a few columns in the table, it's easy to simply put [p_x],[p_y],[p_z], but obviously it's not convenient to type 50 or more columns. Even though you may use this trick to drag and drop, or copy/paste, the column names from the table, it's still bulky. And for that, you may use the SELECT * EXCEPT strategy with dynamic sql.
DECLARE #TSQL NVARCHAR(MAX), #colNames NVARCHAR(MAX)
SELECT #colNames = COALESCE(#colNames + ',' ,'') + [name]
FROM syscolumns WHERE name <> 'ID' and id = (SELECT id FROM sysobjects WHERE name = 'tablelName')
SET #TSQL = '
WITH CTE AS (
SELECT *
FROM
(
SELECT ID, colName, val
FROM tablelName
UNPIVOT
(
val
FOR colName IN (' + #colNames + ')
) unpiv
) src
PIVOT
(
MAX(val)
FOR ID IN ([11], [12])
) piv
)
--SELECT colName
SELECT *
FROM CTE WHERE [11] != [12]
'
EXEC sp_executesql #TSQL
Here's one way using UNPIVOT:
;WITH
cte AS
(
SELECT CASE WHEN t1.p_x <> t2.p_x THEN 1 ELSE 0 END As p_x,
CASE WHEN t1.p_y <> t2.p_y THEN 1 ELSE 0 END As p_y,
CASE WHEN t1.p_z <> t2.p_z THEN 1 ELSE 0 END As p_z
FROM MyTable t1, MyTable t2
WHERE t1.ID = 11 AND t2.ID = 12 -- enter the two revisions to compare here
)
SELECT *
FROM cte
UNPIVOT (
Changed FOR ColumnName IN (p_x, p_y, p_z)
) upvt
WHERE upvt.Changed = 1
You have to add code to handle NULLs during the comparisons. You can also build the query dynamically if there are lots of columns in your table.
for sql server 2012 you can do something like that (duplicate it for
each column):
SELECT iif((p_x != lead(p_x) over(ORDER BY p_x)),
(SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'tbl'
AND
TABLE_SCHEMA='schema'
AND
ORDINAL_POSITION='1')
,NULL)
FROM tbl
for sql server 2008 try
DECLARE #x int =11 -- first id
WHILE #x!=(SELECT count(1) FROM tbl)
BEGIN --comparison of two adjacent rows
if (SELECT p_x FROM tbl WHERE id=#x)!=(SELECT p_x FROM tbl WHERE id=#x+1)
BEGIN
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'tbl' --insert your table
AND
TABLE_SCHEMA='schema' --insert your schema
AND
ORDINAL_POSITION='1' --first column 'p_x'
END
set #x=#x+1
END
Is there a way to nest CASE-WHEN statements in an IN() statement such that one of the WHEN or ELSE returns a subquery. To me, it should not be an issue, but somehow I am getting error:
"Subquery returned more than 1 value."
IN() is supposed to handle more than one values!
Here is a small example to reproduce the error:
-- tblA will be searched for values
Declare #tblA table (i int)
insert #tblA
select 1
union select 2
union select 3
--tblB: its values will be searched in tblA
Declare #tblB table (i int)
insert #tblB
select 2
union select 3
union select 1
--#c used by the CASE statement to match
declare #c varchar(50)
set #c = 'Match'
select *
from #tblA
where i IN ( -- IN statement should accept subquery in it
case #c
when 'Dont Match' then 2 --If it had matched, then the single value 2 would have been returned and TSQL would be happy
else (
select i from #tblB --TSQL not happy and causing error when more than one values returned from the subquery
)
end
)
try
select *
from #tblA A
WHERE (#c = 'Dont Match' AND i = 2) OR
(#c <> 'Dont Match' AND EXISTS (SELECT * FROM #tblB WHERE i = A.i)
Your problem is NOT with the IN clause but with the CASE.CASE cant handle multiple values.
Valid
DECLARE #TBLA TABLE (I INT)
INSERT INTO #TBLA
( [I] )
SELECT 0
SELECT [Result]=CASE WHEN 1=2 THEN
(SELECT I FROM #TBLA T)
ELSE
(SELECT I FROM #TBLA T)
END
Invalid since the table variable contains two records.
DECLARE #TBLA TABLE (I INT)
INSERT INTO #TBLA
( [I] )
SELECT 0
UNION
SELECT 1
SELECT [Result]=CASE WHEN 1=2 THEN
(SELECT I FROM #TBLA T)
ELSE
(SELECT I FROM #TBLA T)
END
IN() is supposed to handle more than one values!
Yes, it actually is. You can see it if you modify your query this way
select *
from #tblA
where i IN ( select i from #tblB )
This query will be executed without errors.
The error was produced by CASE statement for it can't get more than 1 value in THEN or ELSE clauses.
I would like to know if there is a way to use an order by clause when updating a table. I am updating a table and setting a consecutive number, that's why the order of the update is important. Using the following sql statement, I was able to solve it without using a cursor:
DECLARE #Number INT = 0
UPDATE Test
SET #Number = Number = #Number +1
now what I'd like to to do is an order by clause like so:
DECLARE #Number INT = 0
UPDATE Test
SET #Number = Number = #Number +1
ORDER BY Test.Id DESC
I've read: How to update and order by using ms sql The solutions to this question do not solve the ordering problem - they just filter the items on which the update is applied.
Take care,
Martin
No.
Not a documented 100% supported way. There is an approach sometimes used for calculating running totals called "quirky update" that suggests that it might update in order of clustered index if certain conditions are met but as far as I know this relies completely on empirical observation rather than any guarantee.
But what version of SQL Server are you on? If SQL2005+ you might be able to do something with row_number and a CTE (You can update the CTE)
With cte As
(
SELECT id,Number,
ROW_NUMBER() OVER (ORDER BY id DESC) AS RN
FROM Test
)
UPDATE cte SET Number=RN
You can not use ORDER BY as part of the UPDATE statement (you can use in sub-selects that are part of the update).
UPDATE Test
SET Number = rowNumber
FROM Test
INNER JOIN
(SELECT ID, row_number() OVER (ORDER BY ID DESC) as rowNumber
FROM Test) drRowNumbers ON drRowNumbers.ID = Test.ID
Edit
Following solution could have problems with clustered indexes involved as mentioned here. Thanks to Martin for pointing this out.
The answer is kept to educate those (like me) who don't know all side-effects or ins and outs of SQL Server.
Expanding on the answer gaven by Quassnoi in your link, following works
DECLARE #Test TABLE (Number INTEGER, AText VARCHAR(2), ID INTEGER)
DECLARE #Number INT
INSERT INTO #Test VALUES (1, 'A', 1)
INSERT INTO #Test VALUES (2, 'B', 2)
INSERT INTO #Test VALUES (1, 'E', 5)
INSERT INTO #Test VALUES (3, 'C', 3)
INSERT INTO #Test VALUES (2, 'D', 4)
SET #Number = 0
;WITH q AS (
SELECT TOP 1000000 *
FROM #Test
ORDER BY
ID
)
UPDATE q
SET #Number = Number = #Number + 1
The row_number() function would be the best approach to this problem.
UPDATE T
SET T.Number = R.rowNum
FROM Test T
JOIN (
SELECT T2.id,row_number() over (order by T2.Id desc) rowNum from Test T2
) R on T.id=R.id
update based on Ordering by the order of values in a SQL IN() clause
Solution:
DECLARE #counter int
SET #counter = 0
;WITH q AS
(
select * from Products WHERE ID in (SELECT TOP (10) ID FROM Products WHERE ID IN( 3,2,1)
ORDER BY ID DESC)
)
update q set Display= #counter, #counter = #counter + 1
This updates based on descending 3,2,1
Hope helps someone.
I had a similar problem and solved it using ROW_NUMBER() in combination with the OVER keyword. The task was to retrospectively populate a new TicketNo (integer) field in a simple table based on the original CreatedDate, and grouped by ModuleId - so that ticket numbers started at 1 within each Module group and incremented by date. The table already had a TicketID primary key (a GUID).
Here's the SQL:
UPDATE Tickets SET TicketNo=T2.RowNo
FROM Tickets
INNER JOIN
(select TicketID, TicketNo,
ROW_NUMBER() OVER (PARTITION BY ModuleId ORDER BY DateCreated) AS RowNo from Tickets)
AS T2 ON T2.TicketID = Tickets.TicketID
Worked a treat!
I ran into the same problem and was able to resolve it in very powerful way that allows unlimited sorting possibilities.
I created a View using (saving) 2 sort orders (*explanation on how to do so below).
After that I simply applied the update queries to the View created and it worked great.
Here are the 2 queries I used on the view:
1st Query:
Update MyView
Set SortID=0
2nd Query:
DECLARE #sortID int
SET #sortID = 0
UPDATE MyView
SET #sortID = sortID = #sortID + 1
*To be able to save the sorting on the View I put TOP into the SELECT statement. This very useful workaround allows the View results to be returned sorted as set when the View was created when the View is opened. In my case it looked like:
(NOTE: Using this workaround will place an big load on the server if using a large table and it is therefore recommended to include as few fields as possible in the view if working with large tables)
SELECT TOP (600000)
dbo.Items.ID, dbo.Items.Code, dbo.Items.SortID, dbo.Supplier.Date,
dbo.Supplier.Code AS Expr1
FROM dbo.Items INNER JOIN
dbo.Supplier ON dbo.Items.SupplierCode = dbo.Supplier.Code
ORDER BY dbo.Supplier.Date, dbo.Items.ID DESC
Running: SQL Server 2005 on a Windows Server 2003
Additional Keywords: How to Update a SQL column with Ascending or Descending Numbers - Numeric Values / how to set order in SQL update statement / how to save order by in sql view / increment sql update / auto autoincrement sql update / create sql field with ascending numbers
SET #pos := 0;
UPDATE TABLE_NAME SET Roll_No = ( SELECT #pos := #pos + 1 ) ORDER BY First_Name ASC;
In the above example query simply update the student Roll_No column depending on the student Frist_Name column. From 1 to No_of_records in the table. I hope it's clear now.
IF OBJECT_ID('tempdb..#TAB') IS NOT NULL
BEGIN
DROP TABLE #TAB
END
CREATE TABLE #TAB(CH1 INT,CH2 INT,CH3 INT)
DECLARE #CH2 INT = NULL , #CH3 INT=NULL,#SPID INT=NULL,#SQL NVARCHAR(4000)='', #ParmDefinition NVARCHAR(50)= '',
#RET_MESSAGE AS VARCHAR(8000)='',#RET_ERROR INT=0
SET #ParmDefinition='#SPID INT,#CH2 INT OUTPUT,#CH3 INT OUTPUT'
SET #SQL='UPDATE T
SET CH1=#SPID,#CH2= T.CH2,#CH3= T.CH3
FROM #TAB T WITH(ROWLOCK)
INNER JOIN (
SELECT TOP(1) CH1,CH2,CH3
FROM
#TAB WITH(NOLOCK)
WHERE CH1 IS NULL
ORDER BY CH2 DESC) V ON T.CH2= V.CH2 AND T.CH3= V.CH3'
INSERT INTO #TAB
(CH2 ,CH3 )
SELECT 1,2 UNION ALL
SELECT 2,3 UNION ALL
SELECT 3,4
BEGIN TRY
WHILE EXISTS(SELECT TOP 1 1 FROM #TAB WHERE CH1 IS NULL)
BEGIN
EXECUTE #RET_ERROR = sp_executesql #SQL, #ParmDefinition,#SPID =##SPID, #CH2=#CH2 OUTPUT,#CH3=#CH3 OUTPUT;
SELECT * FROM #TAB
SELECT #CH2,#CH3
END
END TRY
BEGIN CATCH
SET #RET_ERROR=ERROR_NUMBER()
SET #RET_MESSAGE = '#ERROR_NUMBER : ' + CAST(ERROR_NUMBER() AS VARCHAR(255)) + '#ERROR_SEVERITY :' + CAST( ERROR_SEVERITY() AS VARCHAR(255))
+ '#ERROR_STATE :' + CAST(ERROR_STATE() AS VARCHAR(255)) + '#ERROR_LINE :' + CAST( ERROR_LINE() AS VARCHAR(255))
+ '#ERROR_MESSAGE :' + ERROR_MESSAGE() ;
SELECT #RET_ERROR,#RET_MESSAGE;
END CATCH