SELECT DISTINCT returns only unique values (without duplicates). DISTINCT operates on a single column. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. Example #List all French customer cities (without duplicates).SELECT DISTINCT City FROM Customer WHERE Country = 'France'...
SELECT DISTINCT agent_code, ord_amount, cust_code, ord_num: This line specifies that you want to retrieve unique combinations of 'agent_code', 'ord_amount', 'cust_code', and 'ord_num'. The DISTINCT keyword ensures that only unique combinations are returned; any duplicate combinations will ...
在SQL中的SELECT语句中使用SELECT函数两次的方法是通过嵌套查询来实现。嵌套查询是指在一个查询语句中嵌套另一个查询语句,将内部查询的结果作为外部查询的一部分。 下面是一个示例,演示如何在SQL中的SELECT语句中使用SELECT函数两次: 代码语言:sql 复制 SELECT column1, column2, (SELECT function_name(column3) FR...
In addition, if you have some raw data, and you’re looking to create reference or “lookup” tables, then using a SQL SELECT DISTINCT with queries is a great way to get the data you’ll insert into those tables. What happens ifSQL DISTINCT and TOP are in the Same Query? Finding and...
In the below example, we can see that sql select statement count will ignore the null values from the specified column on which we are using sql select distinct count clause. Select count (distinct id) from sql_distinct; In the above example, we can see that this statement will ignore the...
After writing the query, click on the execute button to check for errors Once the query is executed, the table appears Select Distinct in SQL A column often contains many duplicate values, and sometimes the information needed from a single column has to be distinct. Using the SELECT DISTINCT ...
尽量使用Select(max,min,sum,avg)和select single,for all enteris,二分法,append和collect loop里不能套select;避免使用select distinct,代替先sort,再delete; ① 抽取数据时,避免使用SELECT *, 尽量使用SELECT A B INTO TABLE ITAB这样的语句。 ② 不要使用SELECT...ENDSELECT语句。
The basic syntax for a SELECT statement is presented below.SELECT [DISTINCT | ALL] {* | select_list} FROM {table_name [alias] | view_name} [{table_name [alias] | view_name}]... [WHERE condition] [GROUP BY condition_list] [HAVING condition] [ORDER BY {column_name | column_# [ ...
SQL 简介:如何使用 SQL SELECT 和 SELECT DISTINCT 图片美国国家标准协会将 SQL 确立为关系数据库管理的标准,因此程序员和管理员只需学习一种语言,只需稍作调整即可适用于各种数据库平台、应用程序和产品。...SQL 是一种具有自己语法的语言,由语句、子句和其他代码片段(例如建立用于限制查询的参数的运算符)组成。....
PostgreSQL has a really interesting and powerful construct calledSELECT DISTINCT ON. No, this is not a typicalDISTINCT. This is different. It is perfect when you have groups of data that are similar and want to pull a single record out of each group, based on a specific ordering. ...