首先,创建一个物化视图。可以使用CREATE MATERIALIZED VIEW语句来创建物化视图,指定视图的名称、列名和查询语句。例如: 首先,创建一个物化视图。可以使用CREATE MATERIALIZED VIEW语句来创建物化视图,指定视图的名称、列名和查询语句。例如: 接下来,为物化视图添加主键约束。可以使用ALTER TABLE语句来
CREATEMATERIALIZEDVIEW<name>[<build_clause>][<create_mv_refresh>]ASsubqueryWhere<build_clause>is: BUILD {IMMEDIATE|DEFERRED}Where<create_mv_refresh>is: REFRESH[COMPLETE][ONDEMAND] Description CREATE MATERIALIZED VIEWdefines a view of a query that isn't updated each time th...
CREATEVIEWteacher_VasSELECTid,b.tnamefromteacher aJOINstudent bONa.id=b.teacher_id; 创建物化视图 CREATEMATERIALIZEDVIEWteacher_MasSELECTid,b.tnamefromteacher aJOINstudent bONa.id=b.teacher_id; 区别分析 01,插入数据 INSERTintostudentVALUES(10001,2,'lipeng'); 02,普通视图查看 SELECT*fromteacher_V ...
创建一个物化视图 CREATEMATERIALIZEDVIEWstudent_view_m ASSELECT*FROMstudentLEFTJOINteacherONstudent.teacher_id=teacher.id; student_view去每个表中进行查询,而student_view_m 直接去视图表查询,而物化视图的查询效率确确实实高于视图不少。 物化视图的数据填充: 物化视图既然是一个实实在在存在的表,它就需要有数...
postgres=# CREATE MATERIALIZED VIEW mvfoo AS SELECT * FROM foo; 创建刷新物化视图的触发器函数 postgres=# CREATE OR REPLACE FUNCTION tri_foo_func() RETURNS TRIGGER AS $$ BEGIN REFRESH MATERIALIZED VIEW mvfoo; RETURN NULL; END; $$ LANGUAGE plpgsql; 由于我们将要创建的是一个AFTER触发器, 所以函数...
CREATE MATERIALIZED VIEW student_view_m AS SELECT * FROM student LEFT JOIN teacher ON student.teacher_id = ; 1. 2. 3. 4. 5. 进行查询explain: master=> explain select * from student_view; QUERY PLAN --- Hash Right Join (cost=16.98..48.34 rows=496 width=448) Hash Cond: ( = student...
CREATE materialized view t_select_counts_per_min as SELECT time , sum(is_query) select_counts FROM doris_sql_audit GROUP BY time 1. 5.2查看物化视图 使用desc doris_sql_audit all来查看doris_sql_audit的物化视图 mysql> desc `doris_sql_audit` all; ...
--创建临时表存储变更CREATETEMPTABLEchangesASSELECT*FROMsource_tableWHERElast_modified>(SELECTMAX(last_refresh)FROMrefresh_metadata);--使用临时表更新物化视图BEGIN;LOCKyour_materialized_viewINSHAREMODE;INSERTINTOyour_materialized_viewSELECT*FROMchangesONCONFLICTDONOTHING;DELETEFROMyour_materialized_viewWHEREidNOTIN...
CREATE FUNCTION Y Y DDL CREATE INDEX Y Y DML CREATE LANGUAGE Y Y DDL CREATE MATERIALIZED VIEW Y N N CREATE OPERATOR Y Y DDL CREATE OPERATOR CLASS Y Y DDL CREATE OPERATOR FAMILY Y Y DDL CREATE PACKAGE Y Y DDL CREATE PACKAGE BODY Y Y DDL CREATE POLICY Y Y DML CREATE PROCEDURE Y Y ...
CTE可以认为是在单个SELECT、INSERT、UPDATE、DELETE 或 CREATE VIEW 语句的执行范围内定义的临时结果集。CTE 与派生表类似,具体表现在不存储为对象,并且只在查询期间有效。与派生表的不同之处在于,CTE 可自引用,还可在同一查询中引用多次。这样开发者就可以更容易地创建可读查询。