CODE EXAMPLE FOR SQL

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

/*Check to see if there are any triggers on the table you are trying to execute 
queries against. They can sometimes throw this error as they are trying to 
run the update/select/insert trigger that is on the table.

You can modify your query to disable then enable the trigger if the trigger 
DOES NOT 
need to be executed for whatever query you are trying to run.*/

ALTER TABLE your_table DISABLE TRIGGER [the_trigger_name]

UPDATE    your_table
SET     Gender = 'Female'
WHERE     (Gender = 'Male')

ALTER TABLE your_table ENABLE TRIGGER [the_trigger_name]