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Differences between variables in other RDBMSes

The differences between variables in each of the RDMSes are outlined as follows:

• Oracle: In Oracle, there is a different syntax for using variables, as shown in the following query:

DECLARE   var_parkname varchar2(100);    var_parkkey varchar2(5) := 'ALB01'; BEGINSELECT parkname INTO var_parkname FROM parks_copyWHERE parkkey = var_parkkey; DBMS_OUTPUT.PUT_LINE(var_parkname);END;

The query has you declare a variable for parkkey (var_parkkey), as well as for the output of the query with the variable in it, which is named var_parkname. Then, you output var_parkname to get the results.

• PostgreSQL: You can't use variables outside of functions.
• SQL Server: In SQL Server, you can't use := to ...