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 2
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...
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...
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 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 indexes including comments including defaults); ...
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);
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 } ...
ifnotexists(select1from t where id=1)insert intot(id,update_time)values(1,getdate())elseupdate t set update_time=getdate()where id=1或者ifexists(select1from t where id=1)insert intot(id,update_time)values(1,getdate())elseupdate t set update_time=getdate()where id=1 ...
test=# create view emp_view as select empno,ename from emp;CREATE VIEWtest=# \sv emp_viewCREATE OR REPLACE VIEW public.emp_view ASSELECT emp.empno,emp.enameFROM emp 四, timing SQL语句执行计时 postgres=# \timing onTiming is on.postgres=# \timing offTiming is off. ...
= 'create index IF NOT EXISTS i'||idxprefix||'_%s on '||quote_ident(v_nsp)||'.'||quote_ident(v_tbl)||' using %s (%I %s) tablespace '||quote_ident(v_tbs)||' ;'; begin for v_attname,v_typid in select attname,atttypid from pg_attribute where not attisdropped and att...