select * from info where id in (select id from depart); 1. 2. 3. 4. not in -- 查找id不等于1或4或6 select * from info where id not in (1,4,6); 1. 2. exists -- 查找是否有select * from depart where id=5,如果有,就查询select * from info select * from info where exists(...
UPDATE table SET field='C', field2='Z' WHERE id=3; INSERT INTO table (id, field, field2) SELECT 3, 'C', 'Z' WHERE NOT EXISTS (SELECT 1 FROM table WHERE id=3); 9.5 以后的版本: INSERT INTO the_table (id, column_1, column_2) VALUES (1, 'A', 'X'), (2, 'B', 'Y...
postgres libpq update 更新速度 非常慢 post the update 这是一个重置密码界面,查看源码可以看到username作了防注入处理逻辑是先通过用户名查出数据,在进行密码的update操作所以要先知道用户名,实际情况中可以注册用户然后实行攻击,这里先用admin演示这和前几个less都不一样,并不能 通过union select进行查询其他数据,但...
*/ if (toastrel_valueid_exists(toastrel, toast_pointer.va_valueid)) { /* Match, so short-circuit the data storage loop below */ data_todo = 0; } } } if (toast_pointer.va_valueid == InvalidOid) { /* * new value; must choose an OID that doesn't conflict in either * old o...
postgres=# update pg_attribute set attnum = 4 where attrelid = 24894 and attname = 'id'; UPDATE 1 postgres=# update pg_attribute set attnum = 2 where attrelid = 24894 and attname = 'vname'; UPDATE 1 postgres=# update pg_attribute set attnum = 1 where attrelid = 24894 and att...
(id) FROM your_table) UNION ALL -- 递归情况:合并两个有序的子数组 SELECT m1.id, m1.value FROM merge_sort m1 JOIN merge_sort m2 ON m1.id > m2.id WHERE NOT EXISTS ( SELECT 1 FROM merge_sort m3 WHERE m3.id > m2.id AND m3.id < m1.id ) ORDER BY m1.id, m2.id ) SELECT ...
IF EXISTS:#该视图不存在时不要抛出一个错误。这种情况下会发出一个提示。...SET/DROP DEFAULT:#这些形式为一个列设置或者移除默认值。对于任何在该视图上的 INSERT 或者 UPDATE 命令,一个视图列的默认值会在引用该视图的任何规则或触发器之前被替换进来。
CREATE TABLE IF NOT EXISTS chats ( id UUID PRIMARY KEY DEFAULT uuid_generate_v4(), chat_name VARCHAR, last_message TIMESTAMP NOT NULL ); FromUPDATE: 不要在目标列的规范中包含表名 因此,要更新的列last_updated不应使用chats.last_updated这样的表名进行限定: ...
ERROR: relation "temp_sales" alreadyexists 解决方法是检查当前会话中是否已经存在同名的临时表。可以使用DROP TABLE命令删除现有的临时表,然后重新创建: DROPTABLEIFEXISTStemp_sales;CREATETEMPORARYTABLEtemp_sales ( sale_id SERIALPRIMARYKEY, product_nameVARCHAR(255), ...
smgrexists(reln, FSM_FORKNUM)) smgrcreate(reln, FSM_FORKNUM, false); /* Invalidate cache so that smgrnblocks() asks the kernel. */ reln->smgr_cached_nblocks[FSM_FORKNUM] = InvalidBlockNumber; fsm_nblocks_now = smgrnblocks(reln, FSM_FORKNUM); /* Extend as needed. */ while (fsm...