postgreSQL如何將表中的多行轉換爲JSON數組

Question

ROW_TO_JSON postgres中的函數將表的一行轉換爲JSON對象。

select row_to_json(result) from (select * from employee) as result; 
select row_to_json(result) from (select * from student) as result; 

給了我三排：

{"salary":null,"age":65,"address":null,"id":111,"name":"NAME"} 
{"salary":null,"age":21,"address":null,"id":222,"name":"SURNAME"} 
{"dob":"1997-03-02","name":"Mediocore","passed":true,"id":555} 

的前兩排是從employee表，而最後一排是從student表。

如果我想將整個結果集從一個表中放入一個JSON對象數組中？ 例如。

[{"salary":null,"age":65,"address":null,"id":111,"name":"NAME"}, {"salary":null,"age":21,"address":null,"id":222,"name":"SURNAME"}]作爲單行而不是兩行分開。

有沒有相當於TABLE_TO_JSON的東西？

Answer 1

也許我錯過了一些東西，但看起來像json_agg應該這樣做。

你也不需要派生表：

select json_agg(row_to_json(employee)) 
from employee;