Hints and tips on mysql
These are some helpful hints on various topics.
apache
bash
cmd
database
java
javascript
linux
mod_rewrite
mssql
mysql
oracle
os
perl
php
regex
rsync
ssh
svn
unix
web_design
windows
Oracle dual table or how to migrate Mysql tableless queries
If you are familiar with Mysql, you probably use sometimes tableless queries like this:SELECT 12 * (1 + 10);
Well, if you're migrating to Oracle you'll be surprised to find that those queries are not allowed here. The solution? Use the dual table like this:
SELECT 12 * (1 + 10) from dual
Dual is special table that is automatically created. Its schema has only one column called dummy, and is populated with just one row with value 'X'. In short - this makes it very useful for our case.