If you are on SQL Server 2017 or Azure, see Mathieu Renda answer.
I had a similar issue when I was trying to join two tables with one-to-many relationships. In SQL 2005 I found that XML PATH
method can handle the concatenation of the rows very easily.
If there is a table called STUDENTS
SubjectID StudentName
---------- -------------
1 Mary
1 John
1 Sam
2 Alaina
2 Edward
Result I expected was:
SubjectID StudentName
---------- -------------
1 Mary, John, Sam
2 Alaina, Edward
I used the following T-SQL
:
SELECT Main.SubjectID,
LEFT(Main.Students,Len(Main.Students)-1) As "Students"
FROM
(
SELECT DISTINCT ST2.SubjectID,
(
SELECT ST1.StudentName + ',' AS [text()]
FROM dbo.Students ST1
WHERE ST1.SubjectID = ST2.SubjectID
ORDER BY ST1.SubjectID
FOR XML PATH ('')
) [Students]
FROM dbo.Students ST2
) [Main]
You can do the same thing in a more compact way if you can concat the commas at the beginning and use substring
to skip the first one so you don't need to do a sub-query:
SELECT DISTINCT ST2.SubjectID,
SUBSTRING(
(
SELECT ','+ST1.StudentName AS [text()]
FROM dbo.Students ST1
WHERE ST1.SubjectID = ST2.SubjectID
ORDER BY ST1.SubjectID
FOR XML PATH ('')
), 2, 1000) [Students]
FROM dbo.Students ST2
From Save MySQL query results into a text or CSV file:
SELECT order_id,product_name,qty
FROM orders
WHERE foo = 'bar'
INTO OUTFILE '/var/lib/mysql-files/orders.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n';
Note: That syntax may need to be reordered to
SELECT order_id,product_name,qty
INTO OUTFILE '/var/lib/mysql-files/orders.csv'
FIELDS TERMINATED BY ','
ENCLOSED BY '"'
LINES TERMINATED BY '\n'
FROM orders
WHERE foo = 'bar';
in more recent versions of MySQL.
Using this command, columns names will not be exported.
Also note that /var/lib/mysql-files/orders.csv
will be on the server that is running MySQL. The user that the MySQL process is running under must have permissions to write to the directory chosen, or the command will fail.
If you want to write output to your local machine from a remote server (especially a hosted or virtualize machine such as Heroku or Amazon RDS), this solution is not suitable.
Best Answer
Version I am using
Update 5th May 2012
Jeff Smith has blogged showing, what I believe is the superior method to get CSV output from SQL Developer. Jeff's method is shown as Method 1 below:
Method 1
Add the comment
/*csv*/
to your SQL query and run the query as a script (using F5 or the 2nd execution button on the worksheet toolbar)That's it.
Method 2
Run a query
Right click and select unload.
Update. In Sql Developer Version 3.0.04 unload has been changed to export Thanks to Janis Peisenieks for pointing this out
Revised screen shot for SQL Developer Version 3.0.04
From the format drop down select CSV
And follow the rest of the on screen instructions.