The following shows how to use the delete() method of the ProductDB class to delete a product with the id 1 from the database table: public class Main { public static void main(String[] args) { int deletedRows = ProductDB.delete(1); System.out.println("Deleted Rows: " + deletedRows...
runoobdb# select * from COMPANY;id|name|age|address|salary---+---+---+---+---1|Paul|32|California|200002|Allen|25|Texas|150003|Teddy|23|Norway|200004|Mark|25|Rich-Mond|650005|David|27|Texas|850006|Kim|22|South-Hall|450007|James|24|Houston|10000(7rows) 以下SQL 语句将删除 ID 为 2...
In PostgreSQL, the DELETE statement is used to remove rows from a table. This can be done conditionally (based on a WHERE clause) to delete specific rows, or without conditions to remove all rows in a table. Proper use of DELETE ensures that only the desired data is removed, while cautio...
*删除表中的字段: alter table [表名] drop column [字段名]; *重命名一个字段: alter table [表名] rename column [字段名A] to [字段名B]; *给一个字段设置缺省值: alter table [表名] alter column [字段名] set default [新的默认值]; *去除缺省值: alter table [表名] alter column [字段...
DELETE FROM table_name WHERE condition LIMIT number_of_rows; 如果你只想删除前面提到的employees表中的前10个薪水低于3000的员工,你可以这样写: DELETE FROM employees WHERE salary < 3000 LIMIT 10; 使用分区表删除数据 如果你的表非常大,删除操作可能会非常耗时,在这种情况下,一种有效的策略是使用分区表,分...
[ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY ] [ FOR { UPDATE | NO KEY UPDATE | SHARE | KEY SHARE } [ OF table_name [, ...] ] [ NOWAIT | SKIP LOCKED ] [...] ] #from_item 可以是以下选项之一 [ ONLY ] table_name [ * ] [ [ AS ] alias [ ( column_...
] ) [ INHERITS ( parent_table [, ... ] ) ] [ WITH OIDS | WITHOUT OIDS ] [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ] [ TABLESPACE tablespace ]column_constraint 可以是以下选项之一:[ CONSTRAINT constraint_name ] { NOT NULL | NULL | UNIQUE [ USING INDEX TABLESPACE tablespac...
CREATE TYPE table_count AS (table_name TEXT, num_rows INTEGER); 2、进行创建一个存储过程 代码语言:javascript 代码运行次数:0 运行 AI代码解释 CREATE OR REPLACE FUNCTION count_em_all (limitNum INTEGER) RETURNS SETOF table_count AS ' DECLARE the_count RECORD; -- 当前行数 t_name RECORD; -...
testdb=# CREATE TABLE t1 (id int, name text);CREATE TABLE 2.3、插入并通过heap_page_items查看数据 2.4、删除数据 1 testdb=# DELETE FROM t1 WHERE id = 1;2 DELETE 13 testdb=# DELETE FROM t1 WHERE id = 2;4 DELETE 156 testdb=...