Question

我在postgres中有一个JSONB数组，格式如下。

{
   "id" : 22323,
   "details" : [
                        {
                            "status" : "stage1",
                             "timestamp" : "2017-09-89"
                         },
                        {
                            "status" : "stage2",
                             "timestamp" : "2017-09-89"
                         }
                        ]
    }

我需要在stage2获取时间戳，如何在postgresql中选择特定状态的时间戳？

Answer 1

如果索引＆＃34;详细信息＆＃34;总是与＆＃34; status＆＃34;：＆＃34; stageVALUE相同，你可以使用 - ＆gt;元素，但如果没有 - 你需要用json_array_elements迭代数组元素，如下所示：

t=# with b as (with v as (select '{
   "id" : 22323,
   "details" : [
                        {
                            "status" : "stage1",
                             "timestamp" : "2017-09-89"
                         },
                        {
                            "status" : "stage2",
                             "timestamp" : "2017-09-89"
                         }
                        ]
    }'::json j)
select json_array_elements(j->'details') j from v)
select j->>'timestamp' from b where j->>'status' = 'stage2'
;
  ?column?
------------
 2017-09-89
(1 row)

如果stage2总是第二个数组元素，则更便宜：

t=# with v as (select '{
   "id" : 22323,
   "details" : [
                        {
                            "status" : "stage1",
                             "timestamp" : "2017-09-89"
                         },
                        {
                            "status" : "stage2",
                             "timestamp" : "2017-09-89"
                         }
                        ]
    }'::json j)
select j->'details'->1->>'timestamp' from v;
  ?column?
------------
 2017-09-89
(1 row)

我使用索引1 cos数组从0

索引

用postgres检查json数组

1 个答案: