Querying Valid-time State Tables

From a column that appeared in Database Programming and Design in the July, 1998 issue.

Examples in Standard SQL-92


Examples in DB2; output from DB2


Examples in Informix


Examples in Oracle; output from Oracle

There was a typo in listing 4 on page 64, in the second union clause. The third predicate should be

(i.e., replace L1.FROM_DATE with L1.TO_DATE). The code samples have been corrected.