You often need data that are stored in separate tables. For example, you may want to produce a report that gets information about flight delays from one table and boarding capacity from another.

Understand the effects of NULLs on inner and outer JOINs Your email has been sent SQL Server developers must understand two things: the difference between inner and outer JOINs and the effect of NULLs ...

This example illustrates a left outer join of the PROCLIB.PAYROLL and PROCLIB.PAYROLL2 tables. proc sql outobs=10; title 'Most Current Jobcode and Salary Information'; select p.IdNumber, p.Jobcode, ...

I need to form the equivalent of a Union Join in Oracle 8i, even though a Union Join doesn't appear to be supported in 8i. I might be able to manipulate a Full Outer Join to get the results I need, ...