最近几年来，地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持，如城市管理、区划、环境整治等等，地理信息成为信息时代重要的组成部分之一； “数字地球”概念的提出，更进一步推动了作为其技术支撑的GIS的发展。 与此同时，一些学者致力于相关的理论研究，如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面，并且这两个方面构成了相互促进的发展过程。
In PostgreSQL ORDER BY Used to sort one or more columns of data in ascending (ASC) or descending (DESC) order. ORDER BY The basic syntax of the clause is as follows: You can use one or more columns in ORDER BY, but you must make sure that the columns you want to sort must exist. ASC Indicates ascending order DESC Indicates descending order. Create the COMPANY table ( 下载 COMPANY SQL 文件 ), the data are as follows: The following example will determine the results based on the The following results are obtained: The following example will determine the results based on the The following results are obtained: The following example will determine the results based on the The following results are obtained: 5.23.1. Grammar ¶
SELECT column-list FROM table_name [WHERE condition] [ORDER BY column1, column2, .. columnN] [ASC | DESC];
5.23.2. Example ¶
runoobdb# select * from COMPANY; id | name | age | address | salary ----+-------+-----+-----------+-------- 1 | Paul | 32 | California| 20000 2 | Allen | 25 | Texas | 15000 3 | Teddy | 23 | Norway | 20000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall| 45000 7 | James | 24 | Houston | 10000 (7 rows)
AGE Field values are sorted in ascending order:runoobdb=# SELECT * FROM COMPANY ORDER BY AGE ASC;
id | name | age | address | salary ----+-------+-----+----------------------------------------------------+-------- 6 | Kim | 22 | South-Hall | 45000 3 | Teddy | 23 | Norway | 20000 7 | James | 24 | Houston | 10000 4 | Mark | 25 | Rich-Mond | 65000 2 | Allen | 25 | Texas | 15000 5 | David | 27 | Texas | 85000 1 | Paul | 32 | California | 20000 (7 rows)
NAME Field values and SALARY Sort the field values in ascending order:runoobdb=# SELECT * FROM COMPANY ORDER BY NAME, SALARY ASC;
id | name | age | address | salary ----+-------+-----+----------------------------------------------------+-------- 2 | Allen | 25 | Texas | 15000 5 | David | 27 | Texas | 85000 7 | James | 24 | Houston | 10000 6 | Kim | 22 | South-Hall | 45000 4 | Mark | 25 | Rich-Mond | 65000 1 | Paul | 32 | California | 20000 3 | Teddy | 23 | Norway | 20000 (7 rows)
NAME Field values are sorted in descending order:runoobdb=# SELECT * FROM COMPANY ORDER BY NAME DESC;
id | name | age | address | salary ----+-------+-----+----------------------------------------------------+-------- 3 | Teddy | 23 | Norway | 20000 1 | Paul | 32 | California | 20000 4 | Mark | 25 | Rich-Mond | 65000 6 | Kim | 22 | South-Hall | 45000 7 | James | 24 | Houston | 10000 5 | David | 27 | Texas | 85000 2 | Allen | 25 | Texas | 15000 (7 rows)