Previous: Value ranges and logical constructions
Up: Aspects of a simple-minded ARCQUERY session
Next: Requests
Previous Page: Value ranges and logical constructions
Next Page: Requests

Table handling

As an example of the usage of table handling facilities, the previous example selection specification can also be made as follows:

SEL/INP=0/OUT=A (OBJECT = N*4151 & DATE <= 3MAR89)



The UNION command combines the two selections A and B in one tabel 1. Similarly, the INTERSECTION function serves to obtain a table of entries which occur in each of two tables, and the DIFFERENCE command will produce a table of entries which appear in only one of two tables.

If, after the union operation, the tables A and B are no longer needed, it is a good idea to delete them with:


You will be prompted for confirmation of the deletion.

Fri Aug 12 10:24:53 BST 1994