从PG1开始,ALTER TABLE DETACH 支持 CONCURRENTLY,避免因ALTER TABLE DETACH忘记设置statement_timeout参数而长时间锁表。 在PG 14版本之前,执行alter table pt_table detach partition part_name;命令会阻塞该分区表(及父表)的所有操作,包括SELECT操作,这是非常严重的。
Subquery –Learn how to write a query nested within another query to form a more flexible queries Correlated Subquery –Show you how to use a correlated subquery to select data that depends on the values of the outer query. Subquery with IN operator –Show you to use a subquery with the ...
SELECT string_agg(a ORDER BY a, ',') FROM table; -- incorrect The latter is syntactically valid, but it represents a call of a single-argument aggregate function with two ORDER BY keys (the second one being rather useless since it's a constant). If DISTINCT is specified in addition to...
2SELECTcount(*)FROMread_parquet('https://shell.duckdb.org/data/tpch/0_01/parquet/orders.parquet')AS(o_orderkeyint); 3SELECTavg(c_acctbal)FROMread_parquet('https://shell.duckdb.org/data/tpch/0_01/parquet/customer.parquet')AS(c_acctbalfloat); 4SELECTcount(*)::intasaws_service_cntFROMre...
IMMV with Aggregate Functions You can create an IMMV that includes aggregate functions. test=#SELECT pgivm.create_immv('immv_agg','SELECT bid, count(*), sum(abalance), avg(abalance)FROM pgbench_accounts JOIN pgbench_branches USING(bid) GROUP BY bid'); NOTICE: created index"immv_agg_...
For these syntaxes, planner internally assigns the name to the subquery when planning joins on tables including it, so join hints are applicable on such joins using the implicit name as the following. postgres=# /*+HashJoin(a1 ANY_subquery)*/ postgres=# EXPLAIN SELECT * postgres=# FROM pgb...
export function notExists(subquery: SQLWrapper): SQL { return sql`not exists (${subquery})`; return sql`not exists ${subquery}`; } /** 2 changes: 2 additions & 0 deletions 2 drizzle-orm/src/utils.ts Original file line numberDiff line numberDiff line change @@ -164,6 +164,8 @@...
Return the Well-Known Binary (WKB) representation of the geometry with SRID meta data. //语法 bytea ST_AsEWKB(geometry g1); bytea ST_AsEWKB(geometry g1, text NDR_or_XDR); //示例 SELECT ST_AsEWKB(ST_GeomFromText('POLYGON((0 0,0 1,1 1,1 0,0 0))',4326)); st_asewkb --...
There are basically two strategies, executing a subquery and join + group by + aggregate.Subquery:select *, array(select row(tbl2.*) from tbl2 where tbl1.id = tbl2.tbl1id) from tbl1Join + group by + aggregate:select tbl1.*, array_agg(tbl2) from tbl1 left join tbl2 on tbl1....
I've created a custom object to get the result of an Raw SQL. I used JSONB to aggregate some data. The object is defined like this: modelBuilder.Entity<PermissionWithScopesByPropertyDto>(entity => { entity.HasNoKey(); entity.Property(e =...