Joining columns and results together is really easy in Oracle or MySQL, in both there is the same function – CONCAT().
However you should be aware that there are differences between the databases on how this function works. In MySQL the CONCAT() function works by joining any number of items specified in the function – I don’t think that there is a limit? But with Oracle it seems that you can only join two strings at a time using this function.
This is the equivalent code for writing a switch statement in Oracle. In Oracle to do the switch we use a function called case. Which looks for a value in the field specified, when it returns true it returns a value else returns a default. This has the same logic as writing an if statement pretty much, e.g. IF (value == “bob”) { do stuff } ELSE….
This is very very handy when having to do some reports and for instance the categories in your database don’t match up to what the report needs or you need combine a few columns together based on their values.
Quite useful, I had the case where I needed to provide a CSV file to an external party from our Oracle 10g database. No problem, there are loads of CSV export tools out there. But it then transpired that the CSV’s that I was generating were using quote (”) marks to identify fields e.g. “field1″,”field2″ and so on…
More below at my main blog site:
Spool a CSV file from Oracle/ SQL*Plus without quotes
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