I got a table Table(id,name), but lets just work with id here
id
--
A
B
C
D
all
What I want is to select all rows (A,B,C D...) except 'all' if the input is all, otherwise only the specific value ( e.g.: A if the input is A ).
Do you guys have some tasty-juicy solution for this one? Thanks!
Let's say you have a parameter #Id in your query. Then you can formulate your WHERE clause based on #Id's value:
SELECT *
FROM MyTable t
WHERE i.Id <> 'all' AND (#Id='all' OR #Id=t.Id)
i.Id <> 'all' part ensures that 'all' row is never returned, regardless of the setting of #Id. The rest is your condition translated to SQL (i.e. either the query has 'all', or the query matches a single Id).
This looks like the wrong usage of a relational table as the "id" column should contain only ids...
I suggest removing the "all" row and instead write a stored procedure to decide whether to select all rows or just one.
Anyway, for your example:
SELECT * FROM your_table WHERE (id = #ID OR #ID = 'all') AND id <> 'all'
Related
I have a stored procedure which takes in five parameters of which two can be null - we will call these parameters A and B
What I would like to do is select records based on the following logic.
If Parameter A is NULL then only return records that match Parameter B
I know that I can do something similar to the following
IF A IS NULL
BEGIN
SELECT * FROM TABLE WHERE Param=B
END
ELSE
BEGIN
SELECT * FROM TABLE WHERE Param=A
END
However, the SQL query is much more complex then the above one and there would be huge replication in the Proc which is something I want to avoid
Thanks in advance
===============================
EDIT - Sorry, I should have mentioned that in the example the Param are based on separate columns e.g.
My table consists of four columns of which two separate columns map to the two parameters - basic schema below
ID
PersonName
GroupID
DeliveryID
In my procedure I want to retrieve those records that match the GroupID however in the scenario where the GroupID is null then I want to return those records that match the DeliveryID
Thanks again
Try
SELECT * FROM my_table WHERE Param = COALESCE(A,B)
COALESCE will give you A if it's not null. Otherwise B.
Functionally, something like this should work. If either parameter is NULL, the condition becomes a self-identity (assuming neither groupID nor deliveryID is NULL).
SELECT *
FROM table_name
WHERE groupID = coalesce(#groupIDParameter, groupID)
AND deliveryID = coalesce(#deliveryIDParameter, deliveryID)
Try ISNULL function:
SELECT * FROM TABLE WHERE Param = ISNULL(B,A)
You could also use a case statement Case when A is Null Then B
I have my sql query like this
if not exists(select RowId from dbo.Cache where StringSearched = #FirstName and colName = 'FirstName')
begin
--some code here
end
The purpose of above if statement is not to execute the piece of code inside of it if value of StringSearched is already present in Cache table which means it has been looked up before and so no need to make calculations again. The code inside of if statement if executed returns row number of rows from Table Band those are then inserted into Cache table to continue maintaining the cache. anyway .I need the records to be picked from Cache only if ModifiedAt column of Cache table is latest than ModifiedAt column of rows of Table B.
Note: I understand that I may need to use a subquery in where clause but in where clause itself, I need to check ModifiedAt column of Table B only for RowId's returned by Outer select query .
How can I proceed without making it much complex ?
You can use the subquery in the current query along with the Where clause.You didn't specified what are the columns to know for figure out which rows to get value so I assumed your tableB also has StringSearched and colName to get max(ModifiedAt) for that string vlaue.
IF NOT EXISTS (SELECT * from dbo.Cache as c WHERE StringSearched = #FirstName
AND colName = 'FirstName'
AND ModifiedAt > (Select MAX(ModifiedAt) FROM tableB as tabB WHERE tabB.RowID = c.RowID ))
BEGIN
--your query
END
Consider the following SQL:
SELECT #Count = COUNT(*)
FROM Widgets
WHERE WidgetName = 'foo'
IF ( #Count = 1 ) BEGIN
SELECT #WidgetId = WidgetId
FROM Widgets
WHERE WidgetName = 'foo'
END
It effectively sets the #WidgetId value, but only if there is exactly one matching row that satisfies the query. The query above is trivial, but consider the case where the WHERE clause is rather expensive. Or if the WHERE clause is more complicated than a single, complete column. (WHERE WidgetName LIKE '%foo%') Is there a way to do a single query to assign the value to the parameter, but only when exactly one row matches, without repeating the WHERE clause?
This will work and won't require you to do more than one single SELECT statement. You will have a lot of freedom on changing the query thereafter, should you need to, without breaking anything.
SELECT #WidgetId = WidgetId
FROM Widgets
WHERE WidgetName = 'foo'
IF ##ROWCOUNT = 1
BEGIN
--Here you are certain that there's only one matching row found
END
ELSE
BEGIN
--Here zero or more than one records were found
END
If I'm understanding correctly, you can use a HAVING clause to successfully only set the #WidgetId variable when the COUNT is equal to one. Something like this should work:
SELECT #WidgetId = MAX(WidgetId)
FROM Widgets
WHERE WidgetName = 'Widget Name'
GROUP BY WidgetName
HAVING COUNT(*) = 1
In the above case, #WidgetId will be set to the MAX(WidgetId) if there is only a COUNT of one record after grouping by WidgetName.
I've created a fiddle that you can look at here: http://www.sqlfiddle.com/#!6/0e303/21
Suppose I have a table with following records
value text
company/about about Us
company company
company/contactus company contact
I have a very simple query in sql server as below. I am having problem with the 'or' condition. In below query, I am trying to find text for value 'company/about'. If it is not found, then only I want to run the other side of 'or'. The below query returns two records as below
value text
company/about about Us
company company
Query
select
*
from
tbl
where
value='company/about' or
value=substring('company/about',0,charindex('/','company/about'))
How can I modify the query so the result set looks like
value text
company/about about Us
A bit roundabout, but you can check for the existence of results from the first where clause:
select
*
from
tbl
where
value='company/about' or
(
not exists (select * from tbl where value='company/about')
and
value=substring('company/about',0,charindex('/','company/about'))
)
Since your second condition can be re-written as value = 'company' this would work (at least for the data and query you've presented):
select top(1) [value], [text]
from dbo.MyTable
where value in ('company/about', 'company')
order by len(value) desc
The TOP() ignores the second row if both are found, and the ORDER BY ensures that the first row is always the one with 'company/about', if it exists.
I am attempting to use a case statement but keep getting errors. Here's the statement:
select TABLE1.acct,
CASE
WHEN TABLE1.acct_id in (select acct_id
from TABLE2
group by acct_id
having count(*) = 1 ) THEN
(select name
from TABLE3
where TABLE1.acct_id = TABLE3.acct_id)
ELSE 'All Others'
END as Name
from TABLE1
When I replace the TABLE1.acct_id in the THEN expression with a literal value, the query works. When I try to use TABLE1.acct_id from the WHEN part of the query, I get a error saying the result is more than one row. It seems like the THEN expression is ignoring the single value that the WHEN statement was using. No idea, maybe this isn't even a valid use of the CASE statement.
I am trying to see names for accounts that have one entry in TABLE2.
Any ideas would be appreciated, I'm kind of new at SQL.
First, you are missing a comma after TABLE1.acct. Second, you have aliased TABLE1 as acct, so you should use that.
Select acct.acct
, Case
When acct.acct_id in ( Select acct_id
From TABLE2
Group By acct_id
Having Count(*) = 1 )
Then ( Select name
From TABLE3
Where acct.acct_id = TABLE3.acct_id
Fetch First 1 Rows Only)
Else 'All Others'
End as Name
From TABLE1 As acct
As others have said, you should adjust your THEN clause to ensure that only one value is returned. You can do that by add Fetch First 1 Rows Only to your subquery.
Then ( Select name
From TABLE3
Where acct.acct_id = TABLE3.acct_id
Fetch First 1 Rows Only)
Fetch is not accepting in CASE statement - "Keyword FETCH not expected. Valid tokens: ) UNION EXCEPT. "
select name from TABLE3 where TABLE1.acct_id = TABLE3.acct_id
will give you all the names in Table3, which have a accompanying row in Table 1. The row selected from Table2 in the previous line doesn't enter into it.
Must be getting more than one value.
You can replace the body with...
(select count(name) from TABLE3 where TABLE1.acct_id = TABLE3.acct_id)
... to narrow down which rows are returning multiples.
It may be the case that you just need a DISTINCT or a TOP 1 to reduce your result set.
Good luck!
I think that what is happening here is that your case must return a single value because it will be the value for the "name" column. The subquery (select acct_id from TABLE2 group by acct_id having count(*) = 1 ) is OK because it will only ever return one value. (select name from TABLE3 where TABLE1.acct_id= TABLE3.acct_id) could return multiple values depending on your data. The problem is you trying to shove multiple values into a single field for a single row.
The next thing to do would be to find out what data causes multiple rows to be returned by (select name from TABLE3 where TABLE1.acct_id= TABLE3.acct_id), and see if you can further limit this query to only return one row. If need be, you could even try something like ...AND ROWNUM = 1 (for Oracle - other DBs have similar ways of limiting rows returned).