mysql nvl

Oracle Study Notes-NVL () function usage skills, learning notes-nvl 1. Rules for alias columns: special characters (except # $), numbers, and spaces must be added with double quotation marks; Chinese characters can be added with double quotation

Talking about mysql which can have nvl functions similar to oracle, oraclenvl Use ifnull instead of isnull Isnull is used to determine whether it is null. If the returned value is 1, it indicates null or 0, it indicates not null. Ifnull is

In Mysql, The ifnull () function is similar to the nvl () function, and nvlifnull IFNULL (expr1, expr2) If expr1 is not NULL, IFNULL () returns expr1; otherwise, it returns expr2. IFNULL () returns a number or string value, depending on the context

SQL ISNULL (), NVL (), ifnull () and coalesce () functions, which are often used in our SQL statements, let's take a look at the example tutorial. p_id ProductName UnitPrice UnitsInStock UnitsOnOrder1 Jarlsberg 10.45 16 152 Mascarpone 32.56 233

Ifnull (EXPR1,EXPR2)If EXPR1 is not Null,ifnull () returns EXPR1, it returns EXPR2. Ifnull () returns a numeric or string value, depending on the context in which it is used.Mysql> Select Ifnull (1,0);1Mysql> Select Ifnull (0,10);0Mysql> Select

Reprinted from: http://blog.sina.com.cn/s/blog_4d4007190100dbch.htmlIfnull (EXPR1,EXPR2)If EXPR1 is not Null,ifnull () returns EXPR1, it returns EXPR2. Ifnull () returns a numeric or string value, depending on the context in which it is used.Mysql>

Mysql and Oracle use the rollup function to complete row and column statistics ??? Yesterday, I suddenly saw in a blog that Mysql also had the rollup function. The original blog post used rollup for row and column statistics. The original blog post

MySQL Master-Slave introductionMySQL master-slave is called replication, AB replication, A and b from the back, write data on a. B will also synchronize A's data, both to achieve real-time synchronizationMySQL is based on the Binlog log to

This article describes how to understand and use the NULL value in MySQL, A friend may refer to the concept of NULL value as a common cause of confusion among SQL beginners. They often think that NULL is the same as an empty string. No! For example,

MySQL's understanding and tutorial on NULL value, mysqlnull The concept of NULL value is a common cause of confusion among SQL beginners. They often think that NULL is the same as an empty string. No! For example, the following statements are