Harry Bailey

UPDATE `table_name`
SET `field_name` = (SELECT CASE `field_name` WHEN 1 THEN 0 ELSE 1 END)
WHERE `id_column` = 1

Or with text strings

UPDATE `table_name`
SET `field_name` = (SELECT CASE `field_name` WHEN 'foo' THEN 'bar' ELSE 'foo' END)
WHERE `id_column` = 1

Some database management tools refuse to admit you can add multiple primary key columns to one table, so you might have to do it with direct sql syntax ( deep intake of breath ).

Multiple primary keys make ‘ON DUPLICATE KEY UPDATE column = column + 100′ type queries a shed load more flexible.

Anyway, on with the code:

ALTER TABLE tablename ADD PRIMARY KEY (column_one, column_two)

And there you have it. Robert’s your fathers brother.