i had red a book recently call"teach yourself sql in 24 hours",there is a question bother me which as follow:Create table EMPLOYEE_TABLE :
( ssn numeric(9) not null,
last_name varchar(20) not null,
first_name varchar(20) not null,
middle_name varchar(20) not null,
st_address varchar(30) not null,
city char(20) not null,
state char(2) not null,
zip numeric(4) not null,
date_hired date);
question is :What statement would you issue on the preceding EMPLOYEE_TABLE to allow the MIDDLE_NAME column to accept NULL values?
I search backward the book carefully,but can't find the answer,
now ask for help, thanks!!!!!!!!
( ssn numeric(9) not null,
last_name varchar(20) not null,
first_name varchar(20) not null,
middle_name varchar(20) not null,
st_address varchar(30) not null,
city char(20) not null,
state char(2) not null,
zip numeric(4) not null,
date_hired date);
question is :What statement would you issue on the preceding EMPLOYEE_TABLE to allow the MIDDLE_NAME column to accept NULL values?
I search backward the book carefully,but can't find the answer,
now ask for help, thanks!!!!!!!!
解决方案 »
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