Article Introduction：CombiningMySQLaggregatefunctionswithMySQLIF()functioncanbeveryhelpfultogetthespecificoutputwewant.ConsiderthefollowingquerieswhichcombineSUM()andCOUNT()aggregatefunctionswithIF()function.Examplemysql>SelectSUM(IF(Language='English&

2023-08-27 comment 0  889

Article Introduction：MySql中DATEDIFF函数和TIMESTAMPDIFF时间函数

2016-06-01 comment 0  1073

Article Introduction：MySQL函数——MySQL系列（六） 1、函数 函数的可移植性不是很强，不同的DBMS有不同的函数 2、文本处理函数 函数 说明 Left() 返回串左边的字符 Length() 返回串的长度 Locate() 找出串的一个子串 Lower() 将串转换为小写 LTrim() 去掉串左边的空 Right() 去掉

2016-06-07 comment 0  997

Article Introduction：MySQL DATE_FORMAT() 函数

2016-05-31 comment 0  1039

Article Introduction：MySQL DATE_ADD()函数

2016-06-01 comment 0  1193

Article Introduction：MYSQL常用函数

2016-05-31 comment 0  1036

Article Introduction：Using MySQL's RAND function to generate random numbers. Random numbers have a wide range of applications in computer science. From game development to cryptography, the generation of random numbers is an important and interesting problem. In the MySQL database, you can use the RAND function to generate random numbers. This article will discuss how to use MySQL's RAND function to generate random numbers and provide some code examples. MySQL's RAND function is a function that generates random numbers. It can generate random floating point numbers between 0 and 1. Using this function, I

2023-07-25 comment 0  3524

Article Introduction：We know that MySQL's OCTET_LENGTH() function also measures the string length in "bytes", so it is a synonym for the MySQLLENGTH() function. The syntax of this function is OCTET_LENGTH(Str), where Str is the character string to be returned. It also does not support multi-byte safety like the LENGTH() function. For example, if a string contains four 2-byte characters, the OCTET_LENGTH() function will return 8. Demonstrated in the following example − Example mysql>SelectOCTET_LENGTH('tutori

2023-08-23 comment 0  1172

Article Introduction：MySQL笔记之数学函数详解

2016-06-01 comment 0  979

Article Introduction：We know that if the first parameter is not NULL, the IFNULL() function will return the first parameter, otherwise it will return the second parameter. On the other hand, the COALESCE() function will return the first non-NULL argument. In fact, if the number of parameters is only two, the IFNULL() and COALESCE() functions in MySQL are equivalent. The reason behind this is that the IFNULL() function only accepts two parameters, in comparison, the COALECSE() function can accept any number of parameters. Suppose we want to use IFNULL() function in place of COALESCE() function, the number of parameters must be two. The following example will demonstrate it -mysql>Se

2023-09-09 comment 0  693

Article Introduction：No, the NVL function in MySQL is not straightforward because it is a non-deterministic function and MySQL cannot use indexes to optimize queries. An alternative is to use the deterministic functions IFNULL or COALESCE, which allow MySQL to use indexes to optimize queries.

2024-05-02 comment 0  742

Article Introduction：How to use MySQL's COUNT function to count the number of rows in a data table. In MySQL, the COUNT function is a very powerful function that is used to count the number of rows in a data table that meet specific conditions. This article will introduce how to use MySQL's COUNT function to count the number of rows in a data table, and provide relevant code examples. The syntax of the COUNT function is as follows: SELECTCOUNT(column_name)FROMtable_nameWHEREconditi

2023-07-25 comment 0  1194

Article Introduction：INSTR() The INSTR(str, substr) function is used to return the index position of the first occurrence of substring substr in the string str. If the substring is not found, it returns 0. For example: selectINSTR('MySQL string function','string')ASindex1,INSTR('MySQL string function','date')ASindex2,INSTR('MySQL string function',&#3

2023-05-28 comment 0  3390

Article Introduction：解析mysql中UNIX_TIMESTAMP()函数与php中time()函数的区别。mysql 中：UNIX_TIMESTAMP(), UNIX_TIMESTAMP(date) 若无参数调用，则返回一个Unix timestamp ('1970-01-01 00:00:00' GMT 之后的秒数) 作为无符号整数。若用date

2016-06-13 comment 0  899

Article Introduction：mysql常用函数参考

2016-06-01 comment 0  995

Article Introduction：MySQL中的聚合函数

2016-06-01 comment 0  1417

Article Introduction：mysql中ADDDATE函数用法

2016-06-01 comment 0  1616

Article Introduction：mysql常用日期时间/数值函数

2016-06-01 comment 0  1005

Article Introduction：The MySQLINSTR() and POSITION() functions work similarly to the LOCATE() function. They are all synonyms for the LOCATE() function. The INSTR() function also returns the position of the first occurrence of the substring after searching within the string. The syntax of INSTR() is as follows - Syntax of INSTR() INSTR(string, substring) Here, String is the string to be searched by MySQL, and substring is the string to be searched. Example mysql>SelectINSTR('Ramisagoodboy','goo

2023-09-05 comment 0  595

Article Introduction：mysql字符串连接函数

2016-06-01 comment 0  943