如何编写 SELECT DISTINCT 查询？

Question

我有一个类别列表，我可以使用 select distinct 语句，但很难“计算”一个类别的使用次数，我有一个名为 Description 的列，我需要创建另一个名为occurrence 的列。

Description
-------------
Arts, crafts, and collectibles
Baby
Beauty and fragrances
Books and magazines
Business to business
Clothing, accessories, and shoes
Computers, accessories, and services
Education
Electronics and telecom
Entertainment and media
Financial services and products
Food retail and service
Gifts and flowers
Government
Health and personal care
Home and garden
Nonprofit
Pets and animals
Religion and spirituality (for profit)
Retail (not elsewhere classified)
Services - other
Sports and outdoors
Toys and hobbies
Travel
Vehicle sales
Vehicle service and accessories
Books and magazines
Business to business
Clothing, accessories, and shoes
Computers, accessories, and services
Education
Electronics and telecom
Entertainment and media
Financial services and products
Food retail and service
Gifts and flowers
Government
Health and personal care
Services - other
Sports and outdoors
Toys and hobbies
Travel
Vehicle sales
Vehicle service and accessories
Books and magazines
Business to business
Clothing, accessories, and shoes
Business to business
Clothing, accessories, and shoes
Computers, accessories, and services
Education
Electronics and telecom
Entertainment and media
Financial services and products
Food retail and service

Answer 1

这听起来像是一个简单的聚合。

Select
   [Description]
   ,Occurences = Count([Description])
From
   YourTable
Group By
   [Description]