This Oracle tutorial explains how to use the Oracle/PLSQL GREATEST function.
GREATEST(a, b, ...) returns the greatest value of the function arguments.
The syntax for the Oracle/PLSQL GREATEST function is:
GREATEST( expr1, expr2, ... expr_n )
expr1, expr2, . expr_n are evaluated by the GREATEST function.
If the data types of the expressions are different,
all expressions will be converted to whatever datatype expr1 is.
SQL> select greatest(12*12,148/2,73) from dual;
-- w w w . j a v a 2s . c o m
GREATEST(12*12,148/2,73)
------------------------
144
SQL>
GREATEST('2', '5', '12', '3')
-----------------------------
'5'
GREATEST('apples', 'oranges', 'bananas')
---------------------------------------
'oranges'