adding conditional statement inside UPDATE - tsql

The query:
UPDATE empPac
SET quantityLimit = allocation,
allocationStart = '"&allocationStart&"',
nextUpdate = DATEADD(mm, allocationMonths, "&allocationStart&"),
lastUpdate = GETDATE(),
quantityIssued = 0,
quantityShipped = 0
WHERE allocation IS NOT NULL AND
allocationMonths <> 0 AND
(nextUpdate <= DATEADD(mm, "&checkCondition&", GETDATE()) OR
nextUpdate IS NULL) AND
empIdent in (select empIdent
from employee
where custIdent='"&custIdent&"')
What I want to do is add a conditional statement to the SET quantityLimit = allocation so that rather than having the WHERE allocation IS NOT NULL, I want it to have a conditional statement such as SET quantityLimit = ((allocation IS NULL) ? 0 : allocation)

You can use ISNULL():
SET quantityLimit = ISNULL(allocation, 0)
Equivalent functions for other databases are NVL() for Oracle and IFNULL() for MySQL and SQLite
What you really should be using though is COALESCE() if you want to increase the portability of your code. COALESCE is part of the SQL-92 standard and widely supported across RDBMSes.

What database do you use?
For example, in oracle sql you can write case when allocation is null then 0 else allocation end or nvl (allocation, 0) or coalesce (allocation, 0)
And case syntax in MSSQL is the same as in Oracle.

This is the TSQL (MSSQL) way:
SET quantityLimit = isnull(allocation,0)
Alternatives...
SET quantityLimit = CASE WHEN allocation is null THEN 0 ELSE allocation END
--This one might be handy if you wanted to check for more than just null values. Such as:
----...CASE WHEN allocation is null THEN 0 WHEN some_other_value THEN 1 WHEN ... THEN ... ELSE allocation END
SET quantityLimit = coalesce(allocation,0)
--This one gives you the first non-null value it finds, given a list of places to look. Such as:
----...coalesce(allocation,some_other_field,some_nuther_field,...,0)

Related

How to use IIf function inside IN Clause?

I have a stored procedure as under
ALTER PROCEDURE [dbo].[usp_testProc]
(#Product NVARCHAR(200) = '',
#BOMBucket NVARCHAR(100) = '')
--exec usp_testProc '','1'
AS
BEGIN
SELECT *
FROM Mytbl x
WHERE 1 = 1
AND (#Product IS NULL OR #Product = '' OR x.PRODUCT = #Product)
AND (#BOMBucket IS NULL OR #BOMBucket = '' OR CAST(x.BOMBucket AS NVARCHAR(100)) IN (IIF(#BOMBucket != '12+', #BOMBucket, '13,14')))
END
Everything else if working fine except when I am passing the bucket value as 12+ . It should ideally show the result for bucket 13 and 14. But the result set is blank.
I know IN expects values as ('13','14'). But somehow not able to fit it in the program.
You can express that logic in a Boolean expression.
...
(#BOMBucket <> '12+'
AND cast(x.BOMBucket AS nvarchar(100)) = #BOMBucket
OR #BOMBucket = '12+'
AND cast(x.BOMBucket AS nvarchar(100)) IN ('13', '14'))
...
But casting the column prevents indexes from being used. You rather should cast the other operand. Like in:
x.BOMBucket = cast(#BOMBucket AS integer)
But then you had the problem, that the input must not be a string representing an inter but can be any string. this would cause an error when casting. In newer SQL Server versions you could circumvent that by using try_cast() but not in 2012 as far as I know. Maybe you should rethink your approach overall and pass a table variable with the wanted BOMBucket as integers instead.

UPDATE with Aggregate SELECT - SET columns 0 when SELECT is empty

I have the following UPDATE statement
UPDATE stuff
SET stuff.total = t.total
FROM (
SELECT SUM(price) FROM things WHERE stuff_id = ? GROUP BY stuff_id
) t
WHERE stuff.id = ?
This works fine when there are actually rows in things, but when not no UPDATE is executed (which I guess makes sense). What would be an elegant way to set stuff.total to 0 in that case? I'd like to do it in one query.
I already tried SET stuff.total = coalesce(t.total, 0) but it had no effect.
You haven't used coalesce in the right place. Also, GROUP BY can be omitted. Try this query:
UPDATE stuff
SET stuff.total = t.total
FROM (
SELECT coalesce(SUM(price), 0) FROM things WHERE stuff_id = ?) t
WHERE stuff.id = ?

How to create an Update statement from a subquery in TSQL

I need to update all records that match my criteria. But the Sql below is giving this error:
Subquery returned more than 1 value. This is not permitted when the
subquery follows =, !=, <, <= , >, >= or when the subquery is used as
an expression.
-- Set MasterAccountId = NULL where there is no Receivable with equivalent BillingAccountId and TaskAccountId
UPDATE R
SET R.MasterAccountId = NULL
FROM Receivable R
WHERE EXISTS ( SELECT * FROM MasterAccount M
WHERE (ISNULL(M.BillingAccountId, 0) > 0 AND M.BillingAccountId = R.BillingAccountId) OR
(ISNULL(M.TaskAccountId, 0) > 0 AND M.TaskAccountId = R.TaskAccountId))
Basically, I need to update all records that return in that subquery.
Does any one know how to fix it?
Can you give a try on this. This is base from the repond of https://stackoverflow.com/users/40655/robin-day on this link How do I UPDATE from a SELECT in SQL Server?.
UPDATE
R
SET
R.MasterAccountId = NULL
FROM
Receivable R
INNER JOIN
MasterAccount M
ON
(ISNULL(M.BillingAccountId, 0) > 0 AND M.BillingAccountId = R.BillingAccountId) OR
(ISNULL(M.TaskAccountId, 0) > 0 AND M.TaskAccountId = R.TaskAccountId))
I don't think you are getting the said error in posted query May be somewhere else. Again in your EXISTS subquery, instead of saying select * ... it's always better to say WHERE EXISTS ( SELECT 1 FROM MasterAccount M
Also try using the JOIN version of this query instead like
UPDATE R
SET R.MasterAccountId = NULL
FROM Receivable R
JOIN MasterAccount M ON M.BillingAccountId = R.BillingAccountId
OR M.TaskAccountId = R.TaskAccountId
WHERE ISNULL(M.BillingAccountId, 0) > 0
OR ISNULL(M.TaskAccountId, 0) > 0;

need to translate specific t-sql case in pl/sql

Can anyone tell me how to translate the following T-SQL statement:
SELECT fileld1 = CASE
WHEN T.option1 THEN -1
ELSE
CASE WHEN T.option2 THEN 0
ELSE 1
END
END
FROM Table1 AS T
The point is I need to validate two different options from the table for a single field in the select statement..
I have tried to do somthing with an IF statement in pl/sql, but it just doesnt work for me:
SELECT IF T.option1 THEN -1
ELSE IF T.option2 THEN 0
ELSE 1
END
FROM Table1 AS T
I am not actually sure how to write IF statement inside the SELECT statement..
And also, I need to do it INSIDE the select statement because I am constructing a view.
Use:
SELECT CASE
WHEN T.option1 = ? THEN -1
WHEN T.option2 = ? THEN 0
ELSE 1
END AS field1
FROM Table1 AS T
I can't get your original TSQL to work - I get:
Msg 4145, Level 15, State 1, Line 4
An expression of non-boolean type specified in a context where a condition is expected, near 'THEN'.
...because there's no value evaluation. If you're checking if the columns are null, you'll need to use:
SELECT CASE
WHEN T.option1 IS NULL THEN -1
WHEN T.option2 IS NULL THEN 0
ELSE 1
END AS field1
FROM Table1 AS T
...or if you need when they are not null:
SELECT CASE
WHEN T.option1 IS NOT NULL THEN -1
WHEN T.option2 IS NOT NULL THEN 0
ELSE 1
END AS field1
FROM Table1 AS T
CASE expressions shortcircuit - if the first WHEN matches, it returns the value & exits handling for that row - so the options afterwards aren't considered.
If I remember correctly, PL/SQL also supports the case. You just would have to move the column alias from "field1=" before the expression to "AS filed1" after the expression.

How to conditionally filter on a column in a WHERE clause?

OK, the umpteenth conditional column question:
I'm writing a stored proc that takes an input parameter that's mapped to one of several flag columns. What's the best way to filter on the requested column? I'm currently on SQL2000, but about to move to SQL2008, so I'll take a contemporary solution if one's available.
The table queried in the sproc looks like
ID ... fooFlag barFlag bazFlag quuxFlag
-- ------- ------- ------- --------
01 1 0 0 1
02 0 1 0 0
03 0 0 1 1
04 1 0 0 0
and I want to do something like
select ID, name, description, ...
from myTable
where (colname like #flag + 'Flag') = 1
so if I call the sproc like exec uspMyProc #flag = 'foo' I'd get back rows 1 and 4.
I know I can't do the part in parens directly in SQL. In order to do dynamic SQL, I'll have to stuff the entire query into a string, concatenate the #flag param in the WHERE clause and then exec the string. Aside from the dirty feeling I get when doing dynamic SQL, my query is fairly large (I'm selecting a couple dozen fields, joining 5 tables, calling a couple of functions), so it's a big giant string all because of a single line in a 3-line WHERE filter.
Alternately, I could have 4 copies of the query and select among them in a CASE statement. This leaves the SQL code directly executable (and subject to syntax hilighting, etc.) but at the cost of repeating big chunks of code, since I can't use the CASE on just the WHERE clause.
Are there any other options? Any tricky joins or logical operations that can be applied? Or should I just get over it and exec the dynamic SQL?
There are a few ways to do this:
You can do this with a case statement.
select ID, name, description, ...
from myTable
where CASE
WHEN #flag = 'foo' then fooFlag
WHEN #flag = 'bar' then barFlag
END = 1
You can use IF.
IF (#flag = 'foo') BEGIN
select ID, name, description, ...
from myTable
where fooFlag = 1
END ELSE IF (#flag = 'bar') BEGIN
select ID, name, description, ...
from myTable
where barFlag = 1
END
....
You can have a complicated where clause with a lot of parentheses.
select ID, name, description, ...
from myTable
where (#flag = 'foo' and fooFlag = 1)
OR (#flag = 'bar' and barFlag = 1) OR ...
You can do this with dynamic sql:
DECLARE #SQL nvarchar(4000)
SELECT #SQL = N'select ID, name, description, ...
from myTable
where (colname like ''' + #flag + 'Flag'') = 1'
EXECUTE sp_ExecuteSQL #SQL, N''
There are more, but I think one of these will get you going.
"Alternately, I could have 4 copies of the query and select among them in a CASE statement."
You don't need to copy your entire query 4 times, just add all the possibilities into the where clauses in your single copy of the query:
select ID, name, description, ...
from myTable
where (#flag = 'foo' and fooFlag = 1) OR (#flag = 'bar' and barFlag = 1) OR ...
What I would do is CASE some variables at the beginning. Example:
DECLARE
#fooFlag int,
#barFlag int,
#bazFlag int,
#quuxFlag int
SET #fooFlag = CASE WHEN #flag = 'foo' THEN 1 ELSE NULL END
SET #barFlag = CASE WHEN #flag = 'bar' THEN 1 ELSE NULL END
SET #bazFlag = CASE WHEN #flag = 'baz' THEN 1 ELSE NULL END
SET #quuxFlag = CASE WHEN #flag = 'quux' THEN 1 ELSE NULL END
SELECT ID, name, description, ...
FROM myTable
WHERE (fooFlag >= ISNULL(#fooFlag, 0) AND fooFlag <= ISNULL(#fooFlag, 1))
AND (barFlag >= ISNULL(#barFlag, 0) AND barFlag <= ISNULL(#barFlag, 1))
AND (bazFlag >= ISNULL(#bazFlag, 0) AND bazFlag <= ISNULL(#bazFlag, 1))
AND (quuxFlag >= ISNULL(#quuxFlag, 0) AND quuxFlag <= ISNULL(#quuxFlag, 1))
The good thing about this query is that, because the possible values for "flags" are bounded, you can calculate all your conditionals as prerequisites instead of wrapping columns in them. This guarantees a high-performance index seek on whichever columns are indexed, and doesn't require writing any dynamic SQL. And it's better than writing 4 separate queries for obvious reasons.
You could have a parameter for each possible flag column, then check if the parameter is null or the value in the column is equal to the parameter. Then you pass in a 1 for the flags that you want to check and leave the others null.
select id, name, description, ...
from myTable
where (#fooFlag is null or fooFlag = #fooFlag) AND
(#barFlag is null or barFlag = #barFlag) AND
...
Honestly, though, this seems like an ideal candidate for building a dynamic LINQ query and skipping the SPROC once you get to SQL2008.
int should be accepted as varchar value
declare #CompanyID as varchar(10) = '' -- or anyother value
select * from EmployeeChatTbl chat
where chat.ConversationDetails like '%'+#searchKey+'%'
and
(
(0 = CASE WHEN (#CompanyID = '' ) THEN 0 ELSE 1 END)
or
(chat.CompanyID = #CompanyID)
)
working
when the companyID is present , then filtration based on it is done, other wise , filtration is skipped.
where
case when #value<>0 then Field else 1 end
=
case when #value<>0 then #value else 1 end