在这种情况下,如果不存在,则很容易使用create index concurrently if not exists。 然而,问题是create index concurrently不是原子的:如果一次尝试部署失败,那么索引将仍被定义了,处于无效状态。这是一个简单的例子: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 ...
CREATE[UNIQUE]INDEX[CONCURRENTLY][[IFNOTEXISTS]name]ON[ONLY]table_name[USINGmethod]({column_name|(expression)}[COLLATEcollation][opclass[(opclass_parameter=value[,...])]][ASC|DESC][NULLS{FIRST|LAST}][,...])[INCLUDE(column_name[,...])][WITH(storage_parameter[=value][,...])][TABLESP...
4.创建索引 --建普通索引(索引名通常为 idx_表名_字段名)CREATEINDEXIFNOTEXISTSidx_my_table_ageONmy_table USING btree (age);--建唯一索引CREATEUNIQUEINDEXCONCURRENTLYIFNOTEXISTSidx_unique_my_table_idONmy_table (id);--组合索引CREATEINDEXIFNOTEXISTSindex_nameONtable_name (column1_name, column2_nam...
alter sequence"t_user_ID_seq"restartwith1increment by1;--创建主键序列 drop indexifexists"t_user_pkey";alter table"t_user"add constraint"t_user_pkey"primarykey("ID"); 根据已有表结构创建表 代码语言:javascript 代码运行次数:0 运行 AI代码解释 create tableifnot exists新表(like 旧表 including ...
postgres=# \help create table Command: CREATE TABLE Description: define a new table Syntax: CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name ( [ { column_name data_type [ STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN | DEFAULT } ...
create index index_name on 注意:使用索引列作为查询条件时,不要在索引列上进行数学运算 select * from emp where sal*12>10000; --这样写条件不会使用索引 select * from emp where sal>10000/12; --这样它就会使用索引 删除索引: drop index 索引名; ...
createtablemytable_duperows_20250317(likemytable);begin;setlocalsession_replication_role='replica';withgoodrowsas(selectmin(ctid)frommytablegroupbyid),mydeleteas(deletefrommytablewherenotexists(select1fromgoodrowswheremin=ctid)returning*)insertintomytable_duperows_20250317select*frommydelete;reset session...
CREATE UNIQUE INDEX CONCURRENTLY vvvv ON vvv(aid) 再次查询可以看到物化视图与基表同步了: 四, 物化视图的自动刷新 物化视图的自动更新需要安装一些特殊的插件例如Apache iceberg(冰山)或者是自己手动创建触发器函数+触发器这样的形式,本例中是触发器函数+触发器 ...
CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] name ] ON [ ONLY ] table_name [ USING method ] ( { column_name | ( expression ) } [ COLLATE collation ] [ opclass [ ( opclass_parameter = value [, ... ] ) ] ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ...
drop index if exists "t_user_pkey"; alter table "t_user" add constraint "t_user_pkey" primary key ("ID"); 根据已有表结构创建表 create table if not exists 新表 (like 旧表 including indexes including comments including defaults);