how can i initialize an stored procedures IN parameter to a default value?

when this stored procedure executes without this parameter, stored procedure should use the d开发者_运维技巧efault value and if this parameter is assigned to a value, stored procedure should execute by assigned value.

Declare a variable, say myVar. Check if the parameter is null. If it is not null you assign it to myVar otherwise you assign the default value.

You can't, that's why it's not mentioned in the documentation.