如何为 SQL 中缺失的日期和时间的所有列添加空值

Question

I have a table with user name, dates, time of day and value associated for every hour. I want to add missing dates for each user for all times of the day with null valued for values.

Answer 1

when u created the set it null

create table tablename
(
 colname as datetime null
)

this will set bydefault its value to null