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)