column2 DESC, ...][OFFSET m {ROW | ROWS}][FETCH { FIRST | NEXT } [ num_rows]{ ROW|ROWS }ONLY];SELECTcolumn1, column2, ...FROMtable[WHERE conditions][ORDER BY column1 ASC, column2 DESC, ...][LIMIT { num_rows| ALL }][OFFSET m {ROW | ROWS}]; ...
CREATE TYPE table_count AS (table_name TEXT, num_rows INTEGER); CREATE OR REPLACE FUNCTION count_em_all () RETURNS SETOF table_count AS ' DECLARE the_count RECORD; t_name RECORD; r table_count%ROWTYPE; BEGIN FOR t_name IN SELECT c.relname FROM pg_catalog.pg_class c LEFT JOIN pg_...
SELECT pg_database.datnameas"database_name", pg_database_size(pg_database.datname)/1024/1024/1024AS size_in_GB FROM pg_database ORDER by size_in_GB DESC; database_name|size_in_gb---+---mumbai|422template1|0template0|0(3rows) 使用元命令获取 Postgres 中所有数据库及其大小的列表 nel...
(1rows) postgres=# grant select on t1 to normal_user; GRANT postgres=# grant insert on t1 to normal_user with grant option; GRANT postgres=# grant update on t1 to public; GRANT postgres=# grant select (a) on t1 to test2; GRANT ...
postgres=# select * from tdsql_pg union all select * from t_appoint_col; id|nickname ---+--- 1|hello tdsql_pg 2|tdsql_pg好 1|tdsql_pg分布式数据库的时代来了 1|hello tdsql_pg (4rows) 过滤重复的记录。 postgres=# select * from...
SELECT COUNT(*) FROM people WHERE inpgconn2018 = 'Y'; 没有开并行的情况下(max_parallel_workers_per_gather=0),查询计划如下: Aggregate (cost=169324.73..169324.74 rows=1 width=8) (actual time=983.729..983.730 rows=1 loops=1) -> Seq Scan on people (cost=0.00..169307.23 rows=7001 width=...
例如,我们查看下 select 语句的语法:postgres=# \help SELECT Command: SELECT Description: retrieve rows from a table or view Syntax: [ WITH [ RECURSIVE ] with_query [, ...] ] SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ] [ * | expression [ [ AS ] output_name ] [...
* PORTAL_UTIL_SELECT: 包含一个实用程序语句,该语句返回一个类似SELECT的结果(例如,EXPLAIN或SHOW)。 * 在第一次执行时,运行语句并将其结果转储到portal tuplestore;然后根据需要将结果返回给客户端。 * * PORTAL_MULTI_QUERY: all other cases. Here, we do not support partial ...
cursor.execute("SELECT * FROM employees;")rows=cursor.fetchall()forrowinrows:print(row)# 关闭游标和连接cursor.close()connection.close() 1. 2. 3. 4. 5. 6. 7. 8. 9. 关系图(ER图) 以下是我们在数据库中使用的表的关系图: EMPLOYEESintegeridPK员工IDstringname员工姓名decimalsalary员工薪水 ...
ALL PRIVILEGES:表示一次性给予可以授予的权限。 OK,增删改查也就是select ,update,insert,delete 和usage应该是可以归于一类的,而select和usage是十分相似的,至少在schema下,两者是基本雷同的,但需要注意的是,授权后的新建对象,比如新建表,usage是无权查询的,而select显然是不存在此类问题的。