b.NAME,array_agg(t.name)FROMbooks bLEFTJOINtags tONt."id"=ANY( STRING_TO_ARRAY( b.tags,',') )GROUPBYb.ID, b.NAMEORDERBYb.ID-- 结果-- 01 Book01 {Tag01}-- 02 Book02 {Tag01,Tag02}-- 03 Book03 {Tag01,Tag02,Tag03}
1. postgresql 某字段用逗号分隔,查询某个值是否在其中 比如有个字段值是 1,2,3 查看1是否在里面 select id, gate_type, gate_name from yg_gate_base_b where'1' = ANY ( STRING_TO_ARRAY( gate_type, ',') ) order by gate_type desc 2. postgresql 某字段用逗号分隔,关联表查询 比如一个表,...
a delimiter, and a text to replace the null values. The STRING_TO_ARRAY() function accepts a string as the first argument, splits it into array elements, and concatenates the array elements using a delimiter/separator. The separator can be any value, such as white space...
1.1 string_agg函数 1.2 array_agg函数 2、窗口函数 2.1 窗口函数语法 2.2 avg()OVER() 2.3 row_number() 2.4 rank() 2.5 dense_rank() 2.6 lag() 2.7 first_value() 2.8 last_value() 2.9 nth_value() 2.10 窗口函数别名的使用 1、聚合函数 ...
方法二:array_to_string(ARRAY_AGG() ,':') 例:select array_to_string(ARRAY_AGG(NAME) ,':') from sql_user_test GROUP BY age; 1. 方法三:自定义group_count()函数,不推荐使用,效率没有string_agg()高 CREATE AGGREGATE GROUP_CONCAT(anyelement) ...
这样可以保护语句不会看到在相同数据上由其他连接执行更新的并发事务造成的不一致数据,为每一个数据库会话提供事务隔离。MVCC 避免了传统的数据库系统的锁定方法,将通过锁争夺最小化的方法来达到多会话并发访问时的性能最大化目的。 PostgreSQL 锁机制浅析
PostgreSQL: SELECT t.dept_id FROM sys_dept t WHERE ‘100’ = ANY (string_to_array(ancestors, ‘,’)) 5、group_concat()函数 MySQL: select a.name,group_concat(distinct city)from user_city a group by a.name; PostgreSQL: select a.name,array_to_string(array_agg(distinct a.city),‘,’...
array_to_string(anyarray, text [, text]) Return Type: text PostgreSQL Version: 9.3 Example: PostgreSQL ARRAY_TO_STRING() function Code: SELECT array_to_string(ARRAY[1, 2, 3, NULL, 5], ',', '*'); Sample Output: array_to_string ...
array_to_string(c.conkey, ' ') ASconstraint_key, CASEconfupdtype WHEN'a'THEN'NO ACTION' WHEN'r'THEN'RESTRICT' WHEN'c'THEN'CASCADE' WHEN'n'THEN'SET NULL' WHEN'd'THEN'SET DEFAULT' ENDASon_update, CASEconfdeltype WHEN'a'THEN'NO ACTION' ...
where 1=1 ) a1 on position( a1.prefix_id in '/'||array_to_string(a0.pathid,'/')||'/' ) >0 left outer join pg_stat_activity a2 -- select * from pg_stat_activity on a0.id = a2.pid order by '/'||array_to_string(a0.pathid,'/'),a0.depth; 输出结果格式如下: 附录三...