sql - 如何在 JSON 数组 (PostgreSQL 9.3) 中查找元素的索引？

Question

我在表中有一些数据 radio responses 我正在汇总，看起来像这样:

SELECT question_id, arr FROM radio_responses;

  question_id |       arr       
-------------+-----------------
          73 | [1,0,0]
          73 | [1,0,0]
          73 | [0,1,0]
          73 | [0,1,0]
          73 | [0,1,0]
          73 | [0,0,1]
          73 | [0,1,0]
          73 | [0,1,0]
          73 | [0,0,1]
          73 | [0,0,1]
          73 | [1,0,0]
          74 | [1,0]
          74 | [0,1]
          74 | [1,0]
          74 | [0,1]
          74 | [1,0]
          74 | [0,1]
          77 | [0,1]
          77 | [0,1]
          77 | [0,1]

我的最终目标是从每个数组中提取 1 的索引。我找不到使用 JSON 类型执行此操作的任何函数，但我确实发现如果我有一个 int[] 数组，我可以使用 idx() 执行此操作。

我尝试了各种解决方案，但它们似乎都依赖于首先取消嵌套数据，这似乎是不必要的，尤其是因为信息在这个过程中丢失了(除非有一些使用 WITH ORDINALITY 的东西，我错过了)。

我使用的是 Postgres 9.3 版。

Answer 1

select      *
          ,(select min(i) + 1
            from   generate_series(0,json_array_length(arr)-1) as gs (i)
            where  (arr->>i)::int = 1
            )                           as ind

from        radio_responses
;

---

+-------------+---------+-----+
| question_id | arr     | ind |
+-------------+---------+-----+
| 73          | [1,0,0] | 1   |
+-------------+---------+-----+
| 73          | [1,0,0] | 1   |
+-------------+---------+-----+
| 73          | [0,1,0] | 2   |
+-------------+---------+-----+
| 73          | [0,1,0] | 2   |
+-------------+---------+-----+
| 73          | [0,1,0] | 2   |
+-------------+---------+-----+
| 73          | [0,0,1] | 3   |
+-------------+---------+-----+
| 73          | [0,1,0] | 2   |
+-------------+---------+-----+
| 73          | [0,1,0] | 2   |
+-------------+---------+-----+
| 73          | [0,0,1] | 3   |
+-------------+---------+-----+
| 73          | [0,0,1] | 3   |
+-------------+---------+-----+
| 73          | [1,0,0] | 1   |
+-------------+---------+-----+
| 74          | [1,0]   | 1   |
+-------------+---------+-----+
| 74          | [0,1]   | 2   |
+-------------+---------+-----+
| 74          | [1,0]   | 1   |
+-------------+---------+-----+
| 74          | [0,1]   | 2   |
+-------------+---------+-----+
| 74          | [1,0]   | 1   |
+-------------+---------+-----+
| 74          | [0,1]   | 2   |
+-------------+---------+-----+
| 77          | [0,1]   | 2   |
+-------------+---------+-----+
| 77          | [0,1]   | 2   |
+-------------+---------+-----+
| 77          | [0,1]   | 2   |
+-------------+---------+-----+