notice of default null

2017-6-5 MondayOne of the requirements today is: The two-tax levy module enters the page filter time default is the current month of the previous one months, and according to the filter results display data, we use the framework of MINIUI.Pit

PHPNotice: session_start (): ps_files_cleanup_dir if PHP installed with apt is used in ubuntu/Debian, this prompt may be reported if Session is used. The code is as follows: PHP Notice: session_start (): ps_files_cleanup_dir: Opendir (/var/lib/php5

If PHP installed with apt is used in ubuntu/Debian, this prompt may be reported when Session is used. Copy codeThe Code is as follows: PHP Notice: session_start (): ps_files_cleanup_dir: Opendir (/var/lib/php5) failed: Permission denied (13) In/home/

PHPNotice: session_start (): ps_files_cleanup_dir if PHP installed with apt is used in ubuntu/Debian, this prompt may be reported if Session is used. The code is as follows: PHP Notice: session_start (): ps_files_cleanup_dir:Opendir (/var/lib/php5

PHP uses a permission denied notice solution encountered by the session, Permissionnotice If you are using apt-installed PHP under Ubuntu/debian, you may have a small chance of encountering this hint when you use the session. Copy the Code code as

A Permission denied Notice solution encountered by the PHP Session, permissionnotice If PHP installed with apt is used in ubuntu/Debian, this prompt may be reported when Session is used. Copy codeThe Code is as follows:PHP Notice: session_start ():

In MySQL, when filtering is non-empty, it is often used to be not null and!=null, both of which are literally the same way of feeling, as in factIt will be a big difference if you try to run it!Why does this happen?Null means nothing, cannot =, >,

NULL pointer Constants An integer constant representing a value of 0, called a null pointer constant. For example: 0, 0L, 1-1 (both are integer constant expressions with a value of 0) and (void*) 0, void* null are NULL pointer constants, NULL

Four myths about indexing using indexes: Effects of null values on indexes Let's do some test data first: Sql> CREATE table t (x int, y int); Table created Note that here I do a unique (federated) index of table T: Sql> Create unique index t_

If the Ubuntu/debian, using apt installed PHP, then in the session, there may be a small probability of encountering this hint. Copy Code code as follows: PHP Notice:session_start (): Ps_files_cleanup_dir: Opendir (/VAR/LIB/PHP5)