t1.admin_optionFROMpg_auth_members t1LEFTJOINpg_authid t2ONt2.oid=t1.roleidLEFTJOINpg_authid t3ONt3.oid=t1.memberLEFTJOINpg_authid t4ONt4.oid=t1.grantor;--查看特定角色的成员SELECTrolnameas"member_name"FROMpg_rolesWHEREoidIN(SELECTmemberFROMpg_auth_membersWHEREroleid=(SELECToidFROMpg_rolesWHE...
条件(3) 条件(4) 条件(5) 内连接处理 inner join 在 RHS inner join 在 LHS join_is_legal() 完备性分析 参考 知乎手机端公式显示不完全,有些外连接的符号渲染不出来,PC 端看起来正常。 所以手机端看公众号方便些: PostgreSQL 优化器如何生成正确的 Join Ordermp.weixin.qq.com/s/HcqIsLQlDfMhvpq8...
正文 1 1. 查询表名称在psql状态下查询表名称：\dt SQL方式查看表名称：SELECT tablename FROM pg_tables; SELECT viewname FROM pg_views WHERE schemaname ='public' PostgreSQL获取数据库中所有view名 视图SELECT viewname FROM ...
name)values(1,'a'),(2,'b'),(3,'c');INSERT03test=>createtablet2 (numint,valuevarchar(10) );CREATETABLEtest=>insertintot2 (num,value)values(1,'xxx'),(3,'yyy'),(5,'zzz');INSERT03test=>select*fromt1crossjoint2;
LEFT JOIN pg_stat_all_tables d ON C.relname = d.relname WHERE c.relname ='你要查询的表名' AND reltuples > 0 AND n_dead_tup > (current_setting('autovacuum_analyze_threshold')::NUMERIC(12,4))+(current_setting('autovacuum_analyze_scale_factor')::NUMERIC(12,4))*reltuples; ...
SELECT * FROM table1 JOIN table2 ON table1.id = table2.id ORDER BY table1.column1, table2.column2; 在这个查询中,ORDER BY子句中的列会按照它们在列表中出现的顺序进行排序。首先,结果会根据table1.column1进行排序,然后在column1的值相同的行中,会根据table2.column2进行排序。 你可以在列名后面添加...
A join creates a set of rows in a temporary table and works on two or more tables, and each table should at least one common field and must maintain a relation between the common fields.
FULL OUTER JOIN:全外连接 3、union:合并两个或多个 SELECT 语句的结果 4、别名 创建表的别名 创建列的别名 5、触发器 触发器是数据库的回调函数,它会在指定的数据库事件发生时自动执行/调用。 PostgreSQL 触发器可以在下面几种情况下触发: *在执行操作之前before(在检查约束并尝试插入、更新或删除之前) ...
FULL JOINThe FULL JOIN keyword selects ALL records from both tables, even if there is not a match. For rows with a match the values from both tables are available, if there is not a match the empty fields will get the value NULL....
SELECTpage_id,count(event_id)FROMpageLEFTJOIN(SELECT*FROMeventWHERE(payload->>'time')::timestamptz >=now() -interval'1 week') recentUSING(tenant_id, page_id)WHEREtenant_id =6ANDpathLIKE'/blog%'GROUPBYpage_id; 由於tenant_id 上的篩選和聯結,Azure Cosmos DB for PostgreSQL 知道可以使用共置分...