2.4 KiB
2.4 KiB
title | localeTitle |
---|---|
SQL Select Distinct Statement | SQL选择Distinct语句 |
SQL选择Distinct语句
介绍
此关键字允许我们获取列中唯一值的列表。本指南将证明这一点。
完整显示学生表中的数据
USE fcc_sql_guides_database;
SELECT studentID, FullName, sat_score, programOfStudy, rcd_Created, rcd_Updated FROM student;
+-----------+------------------------+-----------+------------------+---------------------+---------------------+
| studentID | FullName | sat_score | programOfStudy | rcd_Created | rcd_Updated |
+-----------+------------------------+-----------+------------------+---------------------+---------------------+
| 1 | Monique Davis | 400 | Literature | 2017-08-16 15:34:50 | 2017-08-16 15:34:50 |
| 2 | Teri Gutierrez | 800 | Programming | 2017-08-16 15:34:50 | 2017-08-16 15:34:50 |
| 3 | Spencer Pautier | 1000 | Programming | 2017-08-16 15:34:50 | 2017-08-16 15:34:50 |
| 4 | Louis Ramsey | 1200 | Programming | 2017-08-16 15:34:50 | 2017-08-16 15:34:50 |
| 5 | Alvin Greene | 1200 | Programming | 2017-08-16 15:34:50 | 2017-08-16 15:34:50 |
| 6 | Sophie Freeman | 1200 | Programming | 2017-08-16 15:34:50 | 2017-08-16 15:34:50 |
| 7 | Edgar Frank "Ted" Codd | 2400 | Computer Science | 2017-08-16 15:35:33 | 2017-08-16 15:35:33 |
| 8 | Donald D. Chamberlin | 2400 | Computer Science | 2017-08-16 15:35:33 | 2017-08-16 15:35:33 |
| 9 | Raymond F. Boyce | 2400 | Computer Science | 2017-08-16 15:35:33 | 2017-08-16 15:35:33 |
+-----------+------------------------+-----------+------------------+---------------------+---------------------+
9 rows in set (0.00 sec)
获取学习领域列表
SELECT DISTINCT programOfStudy FROM student;
+------------------+
| programOfStudy |
+------------------+
| Literature |
| Programming |
| Computer Science |
+------------------+
3 rows in set (0.00 sec)
与所有这些SQL事物一样,它们比本入门指南中的内容更多。
我希望这至少足以让你开始。
请参阅您的数据库管理员手册,并自己尝试不同的选项。