In PostgreSQL TRUNCATE TABLE Used to delete the data of the table, but not the table structure.
It can also be used DROP TABLE Delete the table, but this command deletes the structure of the table, and if you want to insert data, you need to recreate the table.
Create The following example uses the The results are as follows: TRUNCATE TABLE Vs. DELETE It has the same effect, but because it doesn’t actually scan the table, it’s faster. In addition TRUNCATE TABLE Tablespaces can be freed immediately without the need for subsequent VACUUM Operation, which is very useful on large tables. The PostgreSQL VACUUM operation is used to free and reuse disk space occupied by update / delete rows. 5.36.1. Grammar ¶
TRUNCATE TABLE The basic syntax is as follows:TRUNCATE TABLE table_name;
5.36.2. Example ¶
COMPANY 表（ 下载 COMPANY SQL 文件 ), the data are as follows: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)
TRUNCATE TABLE To clean up COMPANY Table:runoobdb=# TRUNCATE TABLE COMPANY;
runoobdb=# SELECT * FROM CUSTOMERS;
id | name | age | address | salary
----+------+-----+---------+--------
(0 rows)