Miscellaneous Functions

Here are three miscellaneous functions you may find useful.

GREATEST and LEAST

These functions find the GREATEST or the LEAST member from a series of expressions—for example,

SQL> SELECT GREATEST('ALPHA', 'BRAVO','FOXTROT', 'DELTA')
  2  FROM CONVERT;

GREATEST
-------
FOXTROT
FOXTROT
FOXTROT

Notice that GREATEST found the word closest to the end of the alphabet. Notice also a seemingly unnecessary FROM and three occurrences of FOXTROT. If FROM is missing, you will get an error. Every SELECT needs a FROM. The particular table used in the FROM has three rows, so the function in the SELECT clause is performed for each of them. ...

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