Course Intermediate  11245

Course Introduction："Self-study IT Network Linux Load Balancing Video Tutorial" mainly implements Linux load balancing by performing script operations on web, lvs and Linux under nagin.

Course Advanced  17581

Course Introduction："Shangxuetang MySQL Video Tutorial" introduces you to the process from installing to using the MySQL database, and introduces the specific operations of each link in detail.

Course Advanced  11291

Course Introduction："Brothers Band Front-end Example Display Video Tutorial" introduces examples of HTML5 and CSS3 technologies to everyone, so that everyone can become more proficient in using HTML5 and CSS3.

Course Introduction：nullif:nullif NOT NULL and NULL:NOT NULL | NULL: Specifies whether the column is allowed to be null. If neither NULL nor NOT NULL is specified, the column is considered to have NULL specified. In MySQL, setting a NULL value for a NOT NULL field does not cause an error. MySQL will automatically convert the NULL value to the default value of the field. Even if you did not explicitly set a default value for this field when defining the table: Generally speaking, MySQL will automatically add a default value for you, such as a NO

2016-07-29 comment 0  1027

Course Introduction：NOT NULL 和NULL。NOTNULL|NULL：指定该列是否允许为空。如果既不指定NULL也不指定NOTNULL，列被认为指定了NULL 在MySQL中， 为一个NOTNULL字段设置NULL值， 它并不会

2016-06-13 comment 0  1010

Course Introduction：The difference between NULL and (NULL) in MySQL is as follows: NULL represents an unknown value, while (NULL) represents an explicit null value. NULL occupies no storage space, while (NULL) occupies one byte. NULL is not equal to any value, while (NULL) is equal to itself. NULL is used to represent missing or inapplicable data, while (NULL) is used to explicitly set a field to null.

2024-05-01 comment 0  1131