Select from multiple tables without a join?
You could try something like this:
Database
ORA-12560: TNS:protocol adaptor error
o to the windows machine that hosts the Oracle database server Go to Start -> Run -> Services.msc in Windows. Locate OracleService < SID > (here OracleServiceORCL) and click on Start to start the oracle database service (if not already running) Once it is up and running, from the command prompt run the following:tnsping < tnsalias > (tnsalias entry you can … Read more
Setting up foreign keys in phpMyAdmin?
If you want to use phpMyAdmin to set up relations, you have to do 2 things. First of all, you have to define an index on the foreign key column in the referring table (so foo_bar.foo_id, in your case). Then, go to relation view (in the referring table) and select the referred column (so in … Read more
Difference between JOIN and INNER JOIN
They are functionally equivalent, but INNER JOIN can be a bit clearer to read, especially if the query has other join types (i.e. LEFT or RIGHT or CROSS) included in it.
SQL Server FOR EACH Loop
SQL is primarily a set-orientated language – it’s generally a bad idea to use a loop in it. In this case, a similar result could be achieved using a recursive CTE:
Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)
Are you connecting to “localhost” or “127.0.0.1” ? I noticed that when you connect to “localhost” the socket connector is used, but when you connect to “127.0.0.1” the TCP/IP connector is used. You could try using “127.0.0.1” if the socket connector is not enabled/working.
How can I return pivot table output in MySQL?
This basically is a pivot table. A nice tutorial on how to achieve this can be found here: http://www.artfulsoftware.com/infotree/qrytip.php?id=78 I advise reading this post and adapt this solution to your needs. Update After the link above is currently not available any longer I feel obliged to provide some additional information for all of you searching for mysql pivot … Read more
CREATE VIEW must be the only statement in the batch
Just as the error says, the CREATE VIEW statement needs to be the only statement in the query batch. You have two option in this scenario, depending on the functionality you want to achieve: Place the CREATE VIEW query at the beginningCREATE VIEW showing as select tradename, unitprice, GenericFlag from Medicine; with ExpAndCheapMedicine(MostMoney, MinMoney) as ( select max(unitprice), min(unitprice) … Read more
Host ‘xxx.xx.xxx.xxx’ is not allowed to connect to this MySQL server
Possibly a security precaution. You could try adding a new administrator account: Although as Pascal and others have noted it’s not a great idea to have a user with this kind of access open to any IP. If you need an administrative user, use root, and leave it on localhost. For any other action specify … Read more
How do composite indexes work?
Composite indexes work just like regular indexes, except they have multi-values keys. If you define an index on the fields (a,b,c) , the records are sorted first on a, then b, then c. Example: