Maximum

In this example you are shows how to use the MAX or MIN functions to find the maximum or minimum over two fields instead of just one.

schema:scott

DROP TABLE t

 CREATE TABLE t(
  id VARCHAR(10),
  x INTEGER,
  y INTEGER );
INSERT INTO t VALUES ('A',1,2);
INSERT INTO t VALUES ('B',4,3);
INSERT INTO t VALUES ('C',5,5);

The function for using MAX over two fields is

max(x,y) = (x + y + ABS(x-y))/2

The function for using MIN over two fields is

min(x,y) = (x + y - ABS(x-y))/2

SELECT id, x, y, (x+y+ABS(x-y))/2 
  FROM t

In MySQL you can also use the GREATEST or LEAST functions to do this.

In Oracle you can also use the GREATEST or LEAST functions to do this.

SQL HACKS

Hack 10 Converting subqueries into joins

Hack 11 Converting aggregate subqueries into joins

Hack 14 Generate Combinations

Hack 16 Search for a String across columns

Hack 24 Multiply Across a Result Set

Hack 25 Keep a running total

Hack 25.5 Splitting and combining columns

Hack 26 Include the rows your JOIN forgot

Hack 30 Calculate the maximum/minimum of two fields

Hack 33 Get values and subtotals in one shot

Hack 50 Combine tables containing different data

Hack 51/52 Display rows as columns

Hack 55 Import Someone Else's Data

Hack 62 Issue Queries Without Using a Table

Hack 63 Generate rows without tables

Hack 70 Combine your queries

Hack 72 Extract a subset of the results

Hack 78 Break it down by Range

Hack 88 Test two values from a subquery

Hack 98 Find and stop long running queries

Hack 100 Run SQL from a Web Page