Column Aliasing

Similar to the abililty to alias the name of a table in the from clause it is also possible to alias column names. An alias can have up to 35 characters (case is significant).

This has several possible uses. One is simply to produce a more informative report, for example:

SELECT COUNT(*) EMPLOYEES
    FROM   EMPLOYEES;

might produce the following output

EMPLOYEES
       42

Another important use is when using the create table as select statement. This allows you to rename a field, or to name a calculated field.

CREATE TABLE INVENTORY AS
    SELECT PROD_ID, SALES * 3 MAX_LEVEL, SALES MIN_LEVEL
    FROM   SALES;

Would create a new table with three fields, PROD_ID, MAX_LEVEL, and MIN_LEVEL.

This chapter has illustrated various complex query constructions possible with Texis, and has touched on the use of Metamorph in conjunction with standard SQL queries. The next chapter will explain Metamorph query language in depth and give examples of its use in locating relevant narrative text.