VALUESlists with very large numbers of rows should be avoided, as you might encounter out-of-memory failures or poor performance.VALUESappearing withinINSERTis a special case (because the desired column types are known from theINSERT's target table, and need not be inferred by scanning theVALUES...
createtablemytable1(aint,bint,namevarchar(50));createtablemytable2(aint,bint,valuevarchar(50));insertintomytable1values(1,1,'111'),(2,2,'222'),(3,3,'333');insertintomytable2values(1,1,'xxx'),(3,3,'yyy'),(5,5,'zzz');select*frommytable1naturalinnerjoinmytable2; updatemytab...
drop table t1; create table t1( c1 serial primary key, c2 text default lpad('',500,md5(random()::text)) ); insert into t1 (values(1, 'a'), (2, 'b'), (3, 'c') ); insert into t1 select * from (values(4, 'a'), (5, 'b'), (6, 'c') ); postgres=# select * fr...
INSERT INTO table [ ( column [, ...] ) ] { DEFAULT VALUES | VALUES ( { expression | DEFAULT } [, ...] ) | query }LISTEN监听一个通知。LISTEN nameLOAD加载或重载一个共享库文件。 LOAD 'filename'LOCK锁定一个表。LOCK [ TABLE ] name [, ...] [ IN lock_mode MODE ] [ NOWAIT ]...
LANGUAGEplpgsql AS $$ DECLARE dateStr varchar; BEGIN SELECT to_char(DATE'tomorrow','YYYYMMDD')INTO dateStr; EXECUTE format('CREATE TABLE tab_%s (LIKE tab INCLUDING INDEXES)', dateStr); EXECUTE format('ALTER TABLE tab ATTACH PARTITION tab_%s FOR VALUES IN (%L)', dateStr, dateStr); ...
statement,你想查看其执行计划的任何SELECT、INSERT、UPDATE、DELETE、VALUES、EXECUTE、DECLARE、CREATE TABLE AS或者CREATE MATERIALIZED VIEW AS语句。 常用组合 一般查询 --在不需要真正执行sql时,需把analyze去掉 explain analyze select … ; 查询缓存及详细信息 ...
简介:PostgreSQL 动态表复制(CREATE TABLE AS & CREATE TABLE LIKE) 前言 项目中有表复制的需求,而且是动态复制,即在存储过程里根据参数数组的值循环复制n张结构(约束、索引等)等一致的一组表,PostgreSQL提供了两种语法来进行表复制,分别是: CREATE TABLE AS ...
Smaller values reduce planning time but might yield inferior query plans.By default, this variable is set the same as from_collapse_limit, which is appropriate for most uses. Setting it to 1 prevents any reordering of explicit JOINs. Thus, the explicit join order specified in the query will ...
CREATE TABLE orders ( order_id SERIAL PRIMARY KEY, customer_id INT, order_date DATE, order_total NUMERIC(10, 2) ); INSERT INTO orders (customer_id, order_date, order_total) VALUES (1, '2023-01-01', 100.50), (2, '2023-01-02', 50.25), ...
SELECT 1 AS column1, 'one' AS column2 UNION ALL SELECT 2, 'two' UNION ALL SELECT 3, 'three'; 更常用的,VALUES可以被用在一个大型 SQL 命令中。 在INSERT中最常用: INSERT INTO films (code, title, did, date_prod, kind) VALUES ('T_601', 'Yojimbo', 106, '1961-06-16', 'Drama')...