使用一个匹配值Postgres获取所有array_agg()值 PostgreSQL是一种开源的关系型数据库管理系统,它支持丰富的数据类型和功能,包括数组类型。在PostgreSQL中,可以使用array_agg()函数来将多个行的值聚合成一个数组。 array_agg()函数接受一个参数作为输入,并返回一个包含所有匹配值的数组。下面是使用匹配值获取所有ar...
SELECT json_build_object( 'unique_values', array_agg(DISTINCT value) ) FROM ( SELECT DISTINCT value FROM your_table ) sub; 在这个例子中,子查询首先选择了唯一的value,然后外部查询将这些唯一的值聚合成一个 JSON 对象。 方法二:使用json_agg和jsonb_array_elements_text 如果你正在处理 JSONB 数据,你...
r.locktype is not distinct from w.locktype and r.database is not distinct from w.database and r.relation is not distinct from w.relation and r.page is not distinct from w.page and r.tuple is not distinct from w.tuple and r.virtualxid is not distinct from w.virtualxid and r.trans...
6. 数组去重 array(SELECT DISTINCT UNNEST regexp_split_to_array('1|2','\|')::int[] ) 7. 判断元素是否在数组中 SELECT 0 = ANY ('{1,2}'::int[]), SELECT 0 = ANY (lanes); 8. 分页大数据量的查询: SELECT id FROM (SELECT id, row_number() over(ORDER BY id) AS rownum FROM wa...
create function sort_array(anyarray) returns anyarray as $$ select array_agg(distinct n order by n) from unnest($1) as t(n); $$ language sql immutable; Then you could do this: create table mytable ( interface integer[2] ); create unique index mytable_uniq on mytable (sort_array...
*aggcontext; int jumpdistinct; } agg_presorted_distinctcheck; /* for EEOP_AGG_PLAIN_TRANS_[INIT_][STRICT_]{BYVAL,BYREF} */ /* for EEOP_AGG_ORDERED_TRANS_{DATUM,TUPLE} */ struct { AggStatePerTrans pertrans; ExprContext *aggcontext; int setno; int transno; int setoff; } agg_trans...
select indrelid::regclass as tablename,array_agg(indexrelid::regclass) as indexes from pg_index group by indrelid,indkey having count(*) >1; 1. 检查长期未使用的索引。 mydb=# select relname,indexrelname,idx_scan from pg_catalog.pg_stat_user_indexes; 1. 检查无效的索引。 mydb=# select...
" ORDER BY wiki_revision.id SEPARATOR ', '), " "dashboards_wikidocumentvisits.visits " "STRING_AGG(DISTINCT auth_user.username, ', ' ORDER BY auth_user.username), " "MAX(dashboards_wikidocumentvisits.visits) visits " "FROM wiki_document " "INNER JOIN wiki_revision ON " " wiki_docum...
Foreign Keys in PostgreSQLUnderstanding PostgreSQL FunctionsUnderstanding DISTINCT in PostgreSQL (With Examples)Data Processing With PostgreSQL Window FunctionsPostgreSQL Joins : A SummaryUnderstanding PostgreSQL Date and Time FunctionsUnderstanding the Postgres string_agg FunctionWhat Is a PostgreSQL Full Outer ...
:distinct (auto applies :array_agg & :to_jsonb) order_by [Symbol or Hash]: Applies an ordering operation (similar to ActiveRecord #order) Note: this option will be ignored if you need to order a DISTINCT Aggregated Array. physical_cat = Category.create!(name: "Physical") products = ...