Postgresql SELECT FROM TABLE with var PostgreSQL是一种开源的关系型数据库管理系统(RDBMS),它支持高级SQL查询语言和广泛的功能。在PostgreSQL中,使用SELECT语句从表中检索数据是非常常见的操作。 在执行SELECT查询时,可以使用变量(var)来指定查询条件或者在查询结果中使用。变量可以是任何合法的数据类型,如整数、字符串...
selecttable_catalog, table_schema, table_name, column_name, ordinal_position, is_nullable, data_type, (selectdescriptionfrompg_description pgdswherepgds.objoid=to_regclass('schema2023'||'.'||'some_info')::REGCLASS::OIDandobjsubid=isc.ordinal_position )asdescriptionfrominformation_schema.columns ...
Currently for a set of 110k entries in the products table and ~ 1.8 million ids returned by the union all selection, the whole query will take about 8 seconds to return. If I can get it below 1 second it would be super. SELECT * FROM products p WHERE p.id IN (...
frompg_class cjoinpg_tables donc.relname=d.tablenamewherec.relnamein(selectnamefromtb)andd.schemaname='tp'orderbyc.relnameasc 6、使用视图查询表名及字段 SELECTdistinctTABLE_NAME,COLUMN_NAMEFROMINFORMATION_SCHEMA.COLUMNSWHEREtable_schema='ods'ANDtable_nameNOTSIMILARTO'%_20[0-9]+' 二、会话及锁...
select column_name, data_type from information_schema.columns where table_catalog = 'sandbox' and table_schema = 'public' and table_name = 'test'; column_name | data_type ---+--- test_id | character varying test_vc | character varying test_n | numeric big_n | bigint ip_addr |...
postgres=# begin;BEGINpostgres=# select*from test;id---1(1rows) 会话2: 代码语言:javascript 复制 postgres=# begin;BEGINpostgres=# alter table test add column a int; 查询锁状态: 代码语言:javascript 复制 postgres=# select l.locktype,l.relation,l.pid,l.mode,l.granted,p.query_start,p.quer...
statistics for the data you’d see with SELECT column FROM table, whereas the stainherit = false row represents the results of SELECT column FROM ONLY table. 其实就是如果pg_statistic系统表中列条目的stainherit字段为true,该行代表所有继承子表列的统计信息;如果为false,该行代表starelid指定表staattnu...
select * from pg_stat_statements order by shared_blks_hit+shared_blks_read desc limit 5; 10、获取数据库当前的回滚事务数以及死锁数 select datname,xact_rollback,deadlocks from pg_stat_database 11、查询访问指定表的慢查询 select * from pg_stat_activity where query ilike '%<table_name>%' and...
ALTER TABLE public."Test_Abc" ADD CONSTRAINT "UNI_Constraint" UNIQUE ("Idno"); create unique index "Uidx_Test_Abc" on public."Test_Abc" ("TelNo"); --建分区表 CREATE TABLE public."Sales" ( id serial primary key, sale_date date not null, ...
-- 建表 create table t1(id int); -- 插入 insert into t1 values(1),(2),(3); -- 查询 select * from t1 where id = 1; 1. 2. 3. 4. 5. 6. 对于select语句,由于我们并没有为t1表创建索引,所以只能通过全表遍历的方式来执行查询。全表遍历会遍历表的所有块,逐条获取块中的元组,判断元组...