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[英]SQL Query with Aggregate function on Left Join of One-to-Many Relationship
[英]PostgreSQL left join query with one to many relationship
我有下表
CREATE TABLE employee(id serial PRIMARY KEY,employee jsonb);
CREATE TABLE perks_details(id serial PRIMARY KEY,details jsonb);
insert into employee(employee) values
('{"name": "name1",
"perks": [
{"id": 123, "valid_from": "T23:28:56.782Z"},
{"id": 456, "valid_from": "T23:28:56.782Z"},
{"id": 789, "valid_from": "T23:28:56.782Z"}
]
}');
insert into perks_details(details) values('{"id":123,"detail1":"lorem","detail2":"lorem"}');
insert into perks_details(details) values('{"id":123,"detail3":"lorem","detail4":"lorem"}');
insert into perks_details(details) values('{"id":456,"detail5":"lorem","detail6":"lorem"}');
如何使用 perks_details 表中的 id 和聚合函數編寫來自employee
左連接perks_details
選擇查詢,以便我的結果數據如下所示:
{
"name": "name1",
"perks": [
{
"id": 123,
"valid_from": "T23:28:56.782Z",
"details": [
{
"id": 123,
"detail1": "lorem",
"detail2": "lorem"
},
{
"id": 123,
"detail3": "lorem",
"detail4": "lorem"
}
]
},
{
"id": 456,
"valid_from": "T23:28:56.782Z",
"details": [
{
"id": 456,
"detail5": "lorem",
"detail6": "lorem"
}
]
},
{
"id": 789,
"valid_from": "T23:28:56.782Z",
"details": []
}
]
}
我嘗試了多種變體,但無法接近工作查詢。 請在這里給我建議/幫助。
更新我有這個帶有左連接的查詢,但結果不是我所期望的
select e.id, perk, perks_details.details
from employee AS e, jsonb_array_elements(employee->'perks') perk
LEFT JOIN perks_details on perks_details.details -> 'id' = perk->'id'
group by e.id, perk.value, perks_details.details;
您好,您可以通過以下方式進行操作:
with cte as (
select t1.employee->>'name' "name",
t2.id, t2.valid_from, json_agg(t3.details) "details"
from employee t1
cross join lateral jsonb_to_recordset(employee->'perks') as t2(id int,valid_from time)
left join perks_details t3 on t2.id::text=t3.details->>'id'
group by 1,2,3
)
select row_to_json(t) from (
select
name,
json_agg(jsonb_build_object('id',id,'valid_from',valid_from,'details',details)) "perks"
from cte group by name
) t
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