In my Select query I just want to to set the alias name of a column based on a sub-query (that is, a value in another table). Is this possible in SQL Server 2008?
Like:
SELECT tax_Amt AS (SELECT tax FROM Purchase.tblTax WHERE tax_ID=#tax_ID)
FROM Table
Any way to achieve the above query?
No, you cannot dynamically set an alias or column name in standard SQL.
You'd have to use dynamic SQL if you want: but note the alias applies to the column therefore all rows have the same alias. You can't vary the alias row by row
Personally, I'd have an extra column called "TaxType" or such because it sounds like you want to vary the name per row. I'd do that anyway even if all rows have the same alias so my client code expects "TaxType"
Try like this:
SELECT (SELECT tax FROM Purchase.tblTax WHERE tax_ID=#tax_ID) AS tax_Amt
FROM Table
Related
If I do SELECT name, ISNULL(license, 0) FROM table; I get a resulting table with the license column having no name ("Column1" on my xml), how do I give it a name in the query so it makes my life easier when manipulating it on my application? I tried finding it but could only find how to rename the column on the table itself, instead of renaming the column on the table generated by the SELECT.
To simplify: ISNULL removes the name of the column in the generated by my SELECT and I want to bring it back.
Just use an alias:
SELECT name, ISNULL(license, 0) AS license FROM table;
From the Microsoft online document (https://learn.microsoft.com/en-us/sql/t-sql/queries/with-common-table-expression-transact-sql?view=sql-server-ver15), it mentioned that the "With" statement can have a column name as an argument, and then it says that:
"The list of column names is optional only if distinct names for all resulting columns are supplied in the query definition."
What is "if distinct names for all resulting columns are supplied in the query definition" actually means? I use the "With" statement very often, but I never specify column names in the argument.
I tried to go through the entire document but it appears nowhere have explained this in further detail.
Does anyone know under what situation I need to put specify the column name?
Thanks in advance!
Quite simply, the resultset of the query that defines the CTE must return a set of columns with distinct names. For example, the following will not work:
with cte as (select 1 as x, 2 as x)
select * from cte;
The resultset has 2 columns named "x". In such a case, you MUST supply the column names in the definition of the cte since the query produces a resultset with duplicate names. So you would need to use the form:
with cte(x, y) as (select 1 as x, 2 as x)
select * from cte;
As a general matter, it is a best practice for any resultset to NOT have duplicate column names.
I'm using Microsoft Query to pull data from MS SQL Server to Excel. Many of my tables have the same column names, for example:
[task].[active]
[user].[active]
[task].[name]
[user].[name]
When I pivot in Excel, only the column names are shown. A pivot filter might have multiple fields called "active" which is very confusing.
I'd like to alias every column with the table name it's from, so that in the filter it would say "task_active" and "user_active". My Excel SELECT statement would be:
SELECT active AS task_active, name AS task_name FROM task...
Is there a quick way to prepend the table name to an alias using a formatting tool? I have Apex SQL Refactor, and Notepad++ but I haven't found a way to do this without having to manually type all of the column names again.
If you populate resultset to datatable then datatable to excel then it will automatically change duplicate column name to col1,col2 etc.
This is not your requirement.you want it to be specific.
Method 1 . Create temp table with desire column name
Insert the result in #temp table
Return #temp table result set
Method 2 : Use dynamic query.
Wht your real query look like ?
I have a code here in the screenshot. At the end of the code you see a "a"
When i try to remove the "a" and run the code, it fails but it works with the "a"
what is the significance of this ?
Edit: Question was originally tagged MySQL. However, the explanation below should still apply for all the major RDBMS.
It is an Aliasname for the Derived Table. A Derived table is basically a sub-select query. In MySQL, every Derived Table should have its own Alias, so that outer Select queries can refer to the columns/expressions from the Derived Table. Without a table name/alias, MySQL cannot determine the origin of a column value unambiguously.
From Docs:
The [AS] tbl_name clause is mandatory because every table in a FROM
clause must have a name. Any columns in the derived table must have
unique names.
i am trying to create a view in sql server.
create view distinct_product as
select distinct name from stg_user_dtlprod_allignmnt_vw order by name;
this is showing an error.
error message is:
The ORDER BY clause is invalid in views, inline functions, derived tables, subqueries, and common table expressions, unless TOP or FOR XML is also specified.
plz help me out where i am wrong.
You could use TOP with a number that is greater than the number of records:
CREATE VIEW [dbo].[distinct_product]
AS
SELECT DISTINCT TOP 10000000 name
FROM stg_user_dtlprod_allignmnt_vw
ORDER BY name
You cannot use TOP 100 PERCENT since the optimizer recognizes that TOP 100 PERCENT qualifies all rows and does not need to be computed at all, so the ORDER BY wouldn't be guaranteed.
A view cannot be sorted with an ORDER BY clause. You need to put the ORDER BY clause into any query that references the view.
A view is not materialized - the data isn't stored, so how could it be sorted? A view is kind of like a stored procedure that just contains a SELECT with no parameters... it doesn't hold data, it just holds the definition of the query. Since different references to the view could need data sorted in different ways, the way that you do this - just like selecting from a table, which is also an unsorted collection of rows, by definition - is to include the order by on the outer query.
You can't order a view like that when it's created as the message states, unless you follow the other answers from Tim / Raphael, but you can order results selected from a view:
So create it in step 1:
create view distinct_product as
select distinct name
from stg_user_dtlprod_allignmnt_vw
Then order it when you retrieve data:
select *
from distinct_product
order by name