SQL Aggregate FunctionsAn aggregate function is a function that performs a calculation on a set of values, and returns a single value.Aggregate functions are often used with the GROUP BY clause of the SELECT statement. The GROUP BY clause splits the result-set into groups of values and the ...
About errors:help@w3schools.com × SQLANDOperator ❮ PreviousNext ❯ The SQL AND Operator TheWHEREclause can contain one or manyANDoperators. TheANDoperator is used to filter records based on more than one condition, like if you want to return all customers from Spain that sta...
SQL HOME SQL Intro SQL Syntax SQL Select SQL Select Distinct SQL Where SQL Order By SQL And SQL Or SQL Not SQL Insert Into SQL Null Values SQL Update SQL Delete SQL Select Top SQL Aggregate Functions SQL Min and Max SQL Count SQL Sum SQL Avg SQL Like SQL Wildcards SQL In SQL Between...
W3Schools 12600 IBM 4500 HAVING... HAVING... was added to SQL because the WHERE keyword could not be used against aggregate functions (like SUM), and without HAVING... it would be impossible to test for result conditions. WHERE关键字在使用集合函数时不能使用,所以在集合函数中加上了HAVING来...
子查询(Subquery):嵌套在其他SQL语句中的查询。 SELECT * FROM table_name WHERE column_name = (SELECT column_name FROM another_table WHERE condition); 聚合函数(Aggregate Functions):计算一组值的汇总信息,如COUNT、SUM、AVG、MAX和MIN。 SELECT COUNT(*) FROM table_name; SELECT SUM(column_name) FROM...
统计函数 aggregate functions 不能用WHERE语句,可以用于HAVING语句 MAX()SUM()MIN()AVG() 算术 /除法,注意小数位数与除数、被除数中最长的数据类型一致,例如:4/3=1,4.0/3.0=1.333...,4/3.0=1.333...。 ROUND(number, digits) 保留某数字(number)小数点后digits位数 ...
SQL provides many built-in functions for performing processing on string or numeric data, the following are the list of categories of Built-In functions based on the type of data used in operation Aggregate Functions Scalar functions Aggregate Functions ...
Learn SQL: Types of relations Learn SQL: Join multiple tables Learn SQL: Aggregate Functions Learn SQL: SQL-Related Jobs Learn SQL: Non-Equi Joins in SQL Server Learn SQL: SQL Injection Learn SQL: Dynamic SQL Learn SQL: How to prevent SQL Injection attacks...
SELECT <Column List>, <Aggregate Function>(<Column Name>)FROM <Table Name>WHERE <Search Condition...
At W3Schools you will find a complete reference for keywords and functions: SQL Keyword Reference MYSQL Functions SQLServer Functions MS Access Functions SQL Quick Reference SQL Data Types Data types and ranges for Microsoft Access, MySQL and SQL Server. ...