mysql - Create Table and assign a query as default value to a field - 


create table `williamhill` (     `id` varchar(50) null,     `nick` varchar(50) null,     `password` varchar(50) null default (select default_password person p p.id = id),     `colonna 4` varchar(50) null ) collate='latin1_swedish_ci' engine=innodb

how can in mysql? i'm trying assign default value table if no value has been specified during creation of new row.

is possible or should use trigger/procedure?

mysql quite explicit cannot done. begin with, syntax default called default value. value expected.

here how documentation describes this:

the default value clause in data type specification indicates default value column. with 1 exception, default value must constant; cannot function or expression.

(the 1 exception current_time people don't realize function.)

many databases allow function calls here. none -- far know -- allow query expressions. however, can emulated in user-defined function.

the work-around use trigger. looking value in table common use of triggers.


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