Set a parameter in select statement - sql

I am trying to set a parameter in the select statement and then pass it to a user defined function in the same statement. Is this possible? If yes, where is my mistake? If no, then I guess I will have to write a cursor and some temporary tables which I want to avoid.
declare #param varchar(1000)
select Pincode, Name,( #param = AlternateName) as AlternateName
,(select Top(1) part from SDF_SplitString (#param,',')) as NewName from PinCodeTable

You can either get all of the fields out as variables, or get the usual set of rows, but you can't mix and match in a single SELECT. Variables are limited to queries that return no more than one row. (Why do I feel like I'm about to learn something frightening?)
If you are writing a stored procedure and doing something like header/trailer rowsets, you can always return a rowset built from variables:
SELECT #Foo = Foo, #Bar = Bar, ... from Headers where Id = 42
SELECT #Foo as Foo -- Return the first rowset.
SELECT Size, Weight, Color from Trailers where Bar = #Bar -- Return second rowset.

Related

How can I replace multiple words of a string in SQL

Is it possible to replace multiple words in a string in sql without using multiple replace functions?
For example I have a string where I need to replace word 'POLYESTER' with 'POLY' , 'COTTON' with 'CTN', 'GRAPHIC' with 'GRPHC' etc in order to keep the string length at a max of say 30 without much loosing the readability of contents in it(can't use substring to limit chars since it can trim the end meaningful parts of string completely). So we decided to short some keywords like above.
Current query I have used :
SELECT
REPLACE(REPLACE('**Some string value **COTTON **Some string value ** POLYESTER', 'POLYESTER', 'POLY'), 'COTTON', 'CTN')
If I have 10 keywords like this, what will be the best way to achieve the result other than using multiple replace function. I am using SQL Server 2012.
considering sql server is your only instrument (not a c# or another application), as a workaroud; use a temp or persistent table to store replacement options.
IF OBJECT_ID('tempdb..#tmp') IS NOT NULL
DROP TABLE #tmp
CREATE TABLE #tmp (
fromText VARCHAR(16),
toText VARCHAR(16)
);
INSERT INTO #tmp (fromText, toText)
VALUES
('POLYESTER', 'POLY'),
('COTTON', 'CTN'),
('GRAPHIC', 'GRPHC')
DECLARE #someValue AS NVARCHAR(MAX) =
'**Some string value **COTTON **Some string value ** POLYESTER';
SELECT #someValue = REPLACE(#someValue, fromText, toText) FROM #tmp;
PRINT #someValue
and the result is:
**Some string value **CTN **Some string value ** POLY.
The answer of mehmetx is actually very nice.
If you need your replacement functionality on a regular basis, you could think about using a normal table instead of a temporary table.
But if you need this logic only once in a while, and performance is not much of an issue, you could avoid the additional replacements table altogether and use a table expression in the FROM clause instead. Something like this:
DECLARE #someValue AS NVARCHAR(MAX) = '**Some string value **COTTON **Some string value ** POLYESTER';
SELECT #someValue = REPLACE(#someValue, fromText, toText)
FROM
(VALUES
('POLYESTER', 'POLY'),
('COTTON', 'CTN'),
('GRAPHIC', 'GRPHC')
) AS S (fromText, toText);
EDIT:
I noticed, that this logic regrettably does not work as expected when used in an UPDATE statement to update existing data in a table.
For that purpose (if needed), I created a user-defined function that performs the replacement logic. I called it MultiReplace. And it does not use the replacement data from a temporary table, but from a "normal" table, which I called Replacements.
The following code demonstrates it. It uses a data table called MyData, which gets updated with all replacements in the Replacements table using the MultiReplace function:
IF OBJECT_ID('MultiReplace') IS NOT NULL
DROP FUNCTION MultiReplace;
IF OBJECT_ID('Replacements') IS NOT NULL
DROP TABLE Replacements;
IF OBJECT_ID('MyData') IS NOT NULL
DROP TABLE MyData;
GO
CREATE TABLE Replacements (
fromText VARCHAR(100),
toText VARCHAR(100)
);
CREATE TABLE MyData (
SomeValue VARCHAR(MAX)
)
GO
CREATE FUNCTION MultiReplace(#someValue AS VARCHAR(MAX))
RETURNS VARCHAR(MAX)
AS
BEGIN
SELECT #someValue = REPLACE(#someValue, fromText, toText) FROM Replacements;
RETURN #someValue;
END;
GO
INSERT INTO MyData (SomeValue)
VALUES
('**Some string value **COTTON **Some string value ** POLYESTER');
INSERT INTO Replacements (fromText, toText)
VALUES
('POLYESTER', 'POLY'),
('COTTON', 'CTN'),
('GRAPHIC', 'GRPHC');
SELECT * FROM MyData;
UPDATE MyData SET SomeValue = dbo.MultiReplace(SomeValue)
SELECT * FROM MyData;
But perhaps using multiple REPLACE statements might be more straightforward after all?...
EDIT 2:
Based on the short conversation in the comments, I could propose a simpler solution that uses multiple REPLACE statements in a clearer way. I have only tested it on SQL Server 2019; I am not sure if it will work correctly on SQL Server 2012.
Again, I use a table called MyData for testing here. But there are no additional database objects anymore.
Regrettably, I did not get it to work with a temporary table containing the replacement values.
-- Preparations:
IF OBJECT_ID('MyData') IS NOT NULL
DROP TABLE MyData;
CREATE TABLE MyData (
SomeValue VARCHAR(MAX)
);
INSERT INTO MyData
VALUES
('**Some string value **COTTON **Some string value ** POLYESTER'),
('**Another string value **GRAPHIC **Another string value ** POLYESTER');
-- Actual work:
SELECT * FROM MyData; -- Show the state before updating
DECLARE #someValue VARCHAR(MAX);
UPDATE MyData
SET
#someValue = SomeValue,
#someValue = REPLACE(#someValue, 'POLYESTER', 'POLY'),
#someValue = REPLACE(#someValue, 'COTTON', 'CTN'),
#someValue = REPLACE(#someValue, 'GRAPHIC', 'GRPHC'),
SomeValue = #someValue;
SELECT * FROM MyData; -- Show the state after updating

Set int var value as wildcard

I've looked into this and I'm just struggling to accept that it isn't possible to do.
I write queries for others to use and normally include some declared variables at the top so the user can "filter" their search at the top of the query and not bother with the rest.
Sometimes the user may not want to specify the values for a particular variable, as they want to return all types. I know this isn't what SQL is for and that there are reporting tools. Any suggestions on how to do this?
DECLARE #foo int, #bar bit
SET #foo = *
SET #bar = *
SELECT *
FROM table
WHERE foo = #foo
AND bar = #bar
* isn't a valid int value and even if an int value could be used as a wildcard, you would need to use LIKE not =.
What you want here is a NULL value and the proper boolean logic.
SELECT {Columns}
FROM [Table]
WHERE (foo = #foo OR #foo IS NULL)
AND (bar = #bar OR #bar IS NULL)
OPTION (RECOMPILE);-- Comment out/remove if you aren't using T-sQL due to incorrect tagging

is it Possible to set variable inside a View in Sql Server?

I want to set a variable in Sql Server that is selecting date from a view the query I am using is
declare #var varchar(20)
set #var = (SELECT Current_Period_SID FROM dbo.VW_Current_Period_SID_USNT)
just wondering is there a way to set variable in a view something like
CREATE VIEW mp_test AS
declare #var varchar(20)
set #var = (SELECT Current_Period_SID FROM dbo.VW_Current_Period_SID_USNT)
GO
Doing this gives Error
No. You can't do that in a view. I'm not even sure what the point of the above view would be since it doesn't return any value. Even if you could, you wouldn't want to. A variable like this can only store one varchar(20) value. Without an "order by" and top statement you would either get an error or a non-deterministic value unless your table happens to only have a single record.
You can easily fake a variable in your view using CTE. You can test-run it in your version of SQL Server.
CREATE VIEW vwImportant_Users AS
WITH params AS (
SELECT
varType='%Admin%',
varMinStatus=1)
SELECT status, name
FROM sys.sysusers, params
WHERE status > varMinStatus OR name LIKE varType
SELECT * FROM vwImportant_Users
yielding output:
status name
12 dbo
0 db_accessadmin
0 db_securityadmin
0 db_ddladmin
also via JOIN
WITH params AS ( SELECT varType='%Admin%', varMinStatus=1)
SELECT status, name
FROM sys.sysusers INNER JOIN params ON 1=1
WHERE status > varMinStatus OR name LIKE varType
also via CROSS APPLY
WITH params AS ( SELECT varType='%Admin%', varMinStatus=1)
SELECT status, name
FROM sys.sysusers CROSS APPLY params
WHERE status > varMinStatus OR name LIKE varType

Select and assign to variable in one statement?

I'd like to display the results of a query, and I'd like to capture a column's value at the same time. The FROM and WHERE are the same in both queries. Can I do both in one query, or is it easier/better to just do the query twice, like this?
DECLARE #fooId INT
SET #fooId = (SELECT FooId FROM Bar WHERE SnuhId = 5)
SELECT * FROM Bar WHERE SnuhId = 5
Unfortunately it has to be done in two operations.
Test:
DECLARE #VAR DATETIME
SELECT #VAR=GETDATE(), GETDATE()
Yields error message 141.
Here's another SO post on this.
If you try to do it in one query, you will get an error msg - A SELECT statement that assigns a value to a variable must not be combined with data-retrieval operations.
To avoid this, the possibilities are
1) Make sure that all columns are assigned to a local variable. Ex
DECLARE #fooId INT
DECLARE #barId INT
SELECT #fooId = FooId, #barId = BarId FROM Bar WHERE SnuhId = 5
2) simply remove '*' from the SELECT statement
SELECT #fooId = FooId, BarId FROM Bar WHERE SnuhId = 5 //remove BarId column from this query
3) If you really need to do both, meaning to assign the value to local variables and to return the columns as a result set, you have to do it in 2 steps instead of combining them into one SELECT statement.
You can do the following to reduce one line:
DECLARE #fooI INT
SET #fooId = (SELECT FooId FROM Bar WHERE SnuhId = 5)
SELECT #fooId as [FooId]
It will reduce unnecessary replication of your query.
I hope this helps.

Complex query filter using Like() in T-SQL

I'm writing a SQL script that we want our accounting team to be able to edit, without dealing with engineering.
The general idea is to have a .sql script, which defines some variables at the top of the query, and then has several complex queries below it that use those variables.
The problem we have is that we want the accounting team to be able to specify the filter to use. For example:
DECLARE #year INT
DECLARE #month INT
DECLARE #filter VARCHAR(30);
SET #year = 2010
SET #month = 7
SET #filter = '%test%'
Here the team can change the month and the year that the subsequent queries return. They can also define ONE filter element, in this example, excluding any records where the username has the string 'test' in it.
My question is whether or not there is a way to specify OR's to a LIKE(). Eg, ideally we'd have the #filter variable as something like '%test%, or %other%. Now I know that's not real syntax, but I'm wondering if there is syntax that lets me achieve that. I've scowered MSDN on the LIKE() syntax with no joy. Should I use some different query expression?
Probably the simplest thing to do would be to just have multiple parameters, though it's not pretty:
SET #filter_1 = '%test%'
SET #filter_2 = '%foo%'
SET #filter_3 = '%'
SET #filter_4 = '%'
SELECT *
FROM BAR
WHERE var LIKE #filter_1
OR var LIKE #filter_2
OR var LIKE #filter_3
OR var LIKE #filter_4
OR var LIKE #filter_5
By defaulting them to %, they will always match by default.
You could also use dynamic SQL and a local table variable. Basically, create a local table with one column, allow them to change the INSERT statements into that table, then define a loop that iterates over the contents of that table to dynamically generate the LIKE clauses. It would work, but it would be a bit more code. The example above is quick and dirty, but I'd guess it's probably sufficient for what you need to do.
I'd use a join with a LIKE predicate. You can execute the following code sample in a query window to see how this works:
DECLARE #tblFilter TABLE
(sFilter nvarchar(MAX) NOT NULL);
INSERT #tblFilter
SELECT * FROM (VALUES ('%one%'), ('%two%'), ('%three%')) v(s);
DECLARE #tblData TABLE
(iId int NOT NULL PRIMARY KEY IDENTITY,
sData nvarchar(MAX));
INSERT #tblData(sData)
SELECT * FROM (VALUES ('one'), ('two three'), ('four')) v(s);
SELECT DISTINCT iId
FROM #tblData d
JOIN #tblFilter f ON d.sData LIKE f.sFilter;
I assume that the different query strings are in the #tblFilter table, which could be a TVP, coming from XML values, from comma-separated values, from a temp table or whatever.