mysql - SQL Replace Other Column -

i've got joomla database need replace entries in "created_by" column new user id, replacement based on entries in "created_by_alias" column.

╔════════════╦══════════════╗
║ created_by            ║ created_by_alias        ║
╠════════════╬══════════════╣
║ 62                            ║ bob dole                      ║
║ 62                            ║ bill clinton                    ║
║ 62                            ║ bob dole                      ║
║ 62                            ║ hillary clinton              ║
╚════════════╩══════════════╝
so, need created_by replaced 1500 when "created_by_alias" bob dole; 1550 when "created_by_alias" bill clinton; 1600 when "created_by_alias" hillary clinton.

i have come following query isn't working:

update candidates set created_by = 1500 created_by_alias (select * candidates created_by_alias 'bob dole')

i error: #1241 - operand should contain 1 column(s)

what missing? in no way coder or query expert , usual resource busy uw exams @ moment.

i think mean:

update candidates set created_by = 1500 created_by_alias ='bob dole' 

the error you're getting because subselect returning 2 fields (62, 'bob dole'), , 2 rows well. error trying tell you, can test 1 value against 1 field (unless use in clause)