Scalar SQL function example - Amazon Redshift
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Scalar SQL function example

The following example creates a function that compares two numbers and returns the larger value. For more information, see CREATE FUNCTION.

create function f_sql_greater (float, float) returns float stable as $$ select case when $1 > $2 then $1 else $2 end $$ language sql;

The following query calls the new f_sql_greater function to query the SALES table and return either COMMISSION or 20 percent of PRICEPAID, whichever is greater.

select f_sql_greater(commission, pricepaid*0.20) from sales;