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
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
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
The concept of null values is a common cause of confusion among novice sql, who often assume that null is the same thing as an empty string. That's not true! For example, the following statements are completely different:
Mysql> INSERT into
From: http://lz12366.iteye.com/blog/673290
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 completely different:
Comparison between MySQL and Oracle: Function 3: mysqloracle
Function
No.
Category
ORACLE
MYSQL
Note
1
Numeric Functions
Round (1.23456, 4)
Round (1.23456, 4)
Same:ORACLE: select round (1.23456
The foundation of Database learning① Open Database Interconnect CONNECTIVITY,ODBC② structured querying language (structured query Language)③ into mysql:mysql-u cz-p cz;Database:show databases of ④ display system;⑤ create database:create database
/*--The following code is the display width setting for the EMP tableCol empno for 9999;Col ename for A10;Col job for A10;Col Mgr for 9999;Col hiredate for A12;Col Sal for 9999;Col Comm for 9999;Col deptno for 99;Set pagesize 20;--Create a new table
Mysql/oracle Database
Oracle database management system is a computer software that manages database access, and is comprised of Oracle databases and Oracle instances
Oracle database: A collection of related operating system files
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