Is there a way in SQL server to alias column names for a particular table and store the aliases somewhere such that you can access the aliases while querying? I have a table where I cannot change column names and I am trying to figure out if there is a way to alias them to make them more user friendly.
CREATE VIEW vw_RenameTable
AS
Begin
Select GoodName1 = DumbName1
,GoodName2 = DumbName2
From MyTable
End
A view would be the natural answer to the question. But, if you want to access the columns in the same table, you can use computed columns:
alter table mytable add bettercolumn as [Bad Ugly Name];
You can then use the computed column in a select on the same table.
Related
I have a table that has just a code for the individual column name like "A1G", "Z8H" etc.
This table is a really huge table. Therefore it would not help to manually add the alias name in the SELECT Statement like.
The description for each column code is stored in a different table:
Now I would like to SELECT * from the first table but with the right column header name.
This is stored in the second table within the filters Schema = 'ABC' and Table = 'A'.
That would be desired output:
How would you do that in SQL?
How can I change the column name?
You would be better off just creating a view with all the columns aliased to your preferred names. Once that's done you can select from the view and get the data back with the headings you want.
Look into Inner Join
Or Left Join.
I am a newbie in Oracle SQL, though I have experience in SQL Server.
In SQL Server, to select the rows from a table with a particular column in front:
select columnName,* from tableName
In Oracle:
select columnName,* from tableName
gives error ORA-00936: missing expression, as below:
Please guide.
I can't view images, but here's what I think you need:
select t.column_name, t.*
from table_name t
i.e. you should prefix that particular column name with a table alias ("t"), and then use the same alias with the asterisk ("t.*") to retrieve all table columns.
In Oracle, if you need to view a column but also all columns, you need to define an alias for the table.
Select columnName, A.*
from tableName A;
few things we need to keep it in mind
Alias name in sql - used to derive the individual column name via select query
When you are going to use *[select all] you don't have to worry about the alias name
But when you try to pull all the columns and some specific fields you want to filter then you should go for "Alias"
Alias its object key to refer the inter column
select stu.studentName,stu.* from student stu;
I have a big table with names and surnames. People search this database via a Web interface. PHP code queries the table with LOWER(#name) = LOWER(name). In order to make the search faster, I want to make a derived column in the table named lower_name and always LOWER() the names before storing. But when it comes to send the results to web interface, I want to show the original ones. However, I don't want to change the table structure. Is there some kind of Index that automatically does the trick or an option to create an "invisible column" in SQL Server or something like that?
You can create a presisted computed column with an index on it:
ALTER TABLE YourTable ADD lower_name AS LOWER(name) PERSISTED
go
CREATE NONCLUSTERED INDEX IX_YourTable_lower_name
ON YourTable (lower_name)
go
You do not INSERT or UPDATE this column, the DB will do it for you and always keep it in sync with your "name" column.
If you don't want to use a computed column you could create a view, that has the LOWER(name) AS lower_name column in it and put an index on that column:
http://msdn.microsoft.com/en-us/library/cc917715.aspx
You have various options:
declare the column Name case-insensitive using the COLLATE clause
compare Name and #Name using the COLLATE clause
create a computed column LowerName AS LOWER(Name) PERSISTED and index this computed column
PHP code queries the table with
LOWER(#name) = LOWER(name)
Thanks in a world of pain. LOWER(name) triggers a table scan. This is not making it faster, it is - brutally - a beginner mistake that kills performance. You should never compare against a calculation of the table fields, unless you ahve the result in a precaculated index (as you can do in SQL Server 2008, for example).
What about
WHERE name LIKE #name
which should ignore case... plus an Index on the name field.
how to convert result of an select sql query into a new table in msaccess ?
You can use sub queries
SELECT a,b,c INTO NewTable
FROM (SELECT a,b,c
FROM TheTable
WHERE a Is Null)
Like so:
SELECT *
INTO NewTable
FROM OldTable
First, create a table with the required keys, constraints, domain checking, references, etc. Then use an INSERT INTO..SELECT construct to populate it.
Do not be tempted by SELECT..INTO..FROM constructs. The resulting table will have no keys, therefore will not actually be a table at all. Better to start with a proper table then add the data e.g. it will be easier to trap bad data.
For an example of how things can go wrong with an SELECT..INTO clause: it can result in a column that includes the NULL value and while after the event you can change the column to NOT NULL the engine will not replace the NULLs, therefore you will end up with a NOT NULL column containing NULLs!
Also consider creating a 'viewed' table e.g. using CREATE VIEW SQL DDL rather than a base table.
If you want to do it through the user interface, you can also:
A) Create and test the select query. Save it.
B) Create a make table query. When asked what tables to show, select the query tab and your saved query.
C) Tell it the name of the table you want to create.
D) Go make coffee (depending on taste and size of table)
Select *
Into newtable
From somequery
I have a query in MS Access which creates a table from two subqueries. For two of the columns being created, I'm dividing one column from the first subquery into a column from the second subquery.
The datatype of the first column is a double; the datatype of the second column is decimal, with scale of 2, but I want the second column to be a double as well.
Is there a way to force the datatype when creating a table through a standard make-table Access query?
One way to do it is to explicitly create the table before putting anything into it.
Your current statement is probably like this:
SELECT Persons.LastName,Orders.OrderNo
INTO Persons_Order_Backup
FROM Persons
INNER JOIN Orders
ON Persons.P_Id=Orders.P_Id
WHERE FirstName = 'Alistair'
But you can also do this:
----Create NewTable
CREATE TABLE NewTable(FirstName VARCHAR(100), LastName VARCHAR(100), Total DOUBLE)
----INSERT INTO NewTableusing SELECT
INSERT INTO NewTable(FirstName, LastName, Total)
SELECT FirstName, LastName,
FROM Person p
INNER JOIN Orders o
ON p.P_Id = o.P_Id
WHERE p.FirstName = 'Alistair'
This way you have total control over the column types. You can always drop the table later if you need to recreate it.
You can use the cast to FLOAT function CDBL() but, somewhat bizarrely, the Access Database Engine cannot handle the NULL value, so you must handle this yourself e.g.
SELECT first_column,
IIF(second_column IS NULL, NULL, CDBL(second_column))
AS second_column_as_float
INTO Table666
FROM MyTest;
...but you're going to need to ALTER TABLE to add your keys, constraints, etc. Better to simply CREATE TABLE first then use INSERT INTO..SELECT to populate it.
You can use CDbl around the columns.
An easy way to do this is to create an empty table with the correct field types and then to an Append-To query and Access will automatically convert the data to the destination field.
I had a similar situation, but I had a make-table query creating a field with NUMERIC datatype that I wanted to be short text.
What I did (and I got the idea from Stack) is to create the table with the field in question as Short Text, and at the same time build a delete query to scrub the records. I think it's funny that a DELETE query in access doesn't delete the table, just the records in it - I guess you have to use a DROP TABLE function for that, to purge a table...
Then, I converted my make-table query to an APPEND query, which I'd never done before... and I just added the running of the DELETE query to my process.
Thank you, Stack Overflow !
Steve
I add a '& ""' to the field I want to make sure are stored as text, and a ' *1 ' (as in multiplying the amount by 1) to the fields I want to store as numeric.
Seems to do the trick.
To get an Access query to create a table with three numeric output fields from input numeric fields, (it kept wanting to make the output fields text fields), had to combine several of the above suggestions. Pre-establish an empty output table with pre-defined output fields as integer, double and double. In the append query itself, multiply the numeric fields by one. It worked. Finally.