SELECT DISTINCT vs SELECT TheSELECT DISTINCTstatement is used when you want to return only unique (distinct) values in the result set. Whereas, a regularSELECTstatement without theDISTINCTkeyword retrieves all rows from the specified columns, including duplicate values. Let's look at an example. ...
Syntax:SELECT[ALL|DISTINCT|DISTINCTROW ] [HIGH_PRIORITY] [STRAIGHT_JOIN] [SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT] [SQL_CACHE|SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS] select_expr [, select_expr ...] [FROMtable_references [PARTITIONpartition_list] [WHEREwhere_condition] [GROUPBY...
SELECTName:'SELECT'Description: Syntax:SELECT[ALL | DISTINCT | DISTINCTROW][HIGH_PRIORITY][STRAIGHT_JOIN][SQL_SMALL_RESULT][SQL_BIG_RESULT][SQL_BUFFER_RESULT]SQL_NO_CACHE[SQL_CALC_FOUND_ROWS]select_expr[, select_expr ...][FROM table_references [PARTITION partition_list][WHERE where_condition]...
syntaxsql 复制 SELECT [ ALL | DISTINCT ] [ TOP ( expression ) [ PERCENT ] [ WITH TIES ] ] <select_list> <select_list> ::= { * | { table_name | view_name | table_alias }.* | { [ { table_name | view_name | table_alias }. ] { column_name | $IDENTITY | $ROWGUID }...
適用於:sql Server Azure SQL 資料庫 Azure SQL 受控執行個體 Microsoft Fabric Microsoft Fabric SQL 資料庫中Microsoft網狀架構倉儲中的 SQL 分析端點 指定查詢所要傳回的資料行。 Transact-SQL 語法慣例 語法 syntaxsql 複製 SELECT [ ALL | DISTINCT ] [ TOP ( expression ) [ PERCENT ] [ WITH TIES ]...
假设我们有一个名为users的表,其中包含id、name和email三个列。我们想查询不重复的name列。可以使用以下SQL语句: SELECTDISTINCTnameFROMusers; 1. 或者使用GROUP BY语句: SELECTnameFROMusersGROUPBYname; 1. 实际案例 接下来,我们通过一个简单的案例来演示不重复查询的应用。假设我们有一个名为orders的表,其中包含...
sql SELECT last_name "Name", salary*12 "Annual Salary" FROM employees; 去除重复行 默认情况下,查询会返回全部行,包括重复行。 SELECTdepartment_idFROMemployees; 在SELECT语句中使用关键字DISTINCT去除重复行 SELECTDISTINCTdepartment_idFROMemployees;
SELECT DISTINCT job_id FROM employees; 3.查询工资大于12000的员工姓名和工资 SELECT last_name, salary FROM employees WHERE salary>12000; 4.查询员工号为176的员工的姓名和部门号 SELECT last_name, department_id FROM employees WHERE employee_id=176; 5.显示表 departments 的结构,并查询其中的全部数据 DE...
select语句用来执行各种查询数据库的操作,是很重要的语句。 1select语句介绍select语句是值从现存的一个或多个表中查看满足条件的数据,其基本语法如下:Syntax:SELECT[ALL | DISTINCT | DISTINCTROW ] [HIGH_PRIORITY] [STRAIGHT_JOIN] select语句并MySQLdump ...
SELECTDISTINCTCountryFROMCustomers; Try it Yourself » Inside a table, a column often contains many duplicate values; and sometimes you only want to list the different (distinct) values. Syntax SELECTDISTINCTcolumn1,column2, ... FROMtable_name; ...