從另一個表中為每個 ID 寫入數組中的每一列獲取值

Question

我有一個看起來像這樣的數據集

樣本_數據_1

select 'Alice' AS ID, 2 AS col1, 5 AS col2, 6 AS col3, 0 AS col4
union all
select 'Bob' AS ID, 1 AS col1, 4 AS col2, -2 AS col3, 7 AS col4

和一個看起來像這樣的數據集。 這為每個 ID 提供了一個重要列的列表

樣本數據_2

select 'Alice' AS ID, [STRUCT('col1' AS column, 1 AS rank), STRUCT('col4' AS column, 2 AS rank), STRUCT('col3' AS column, 3 AS rank)] AS important_columns
union all
select 'Bob' AS ID, [STRUCT('col4' AS column, 1 AS rank), STRUCT('col2' AS column, 2 AS rank), STRUCT('col1' AS column, 3 AS rank)]

我想為 sample_data_1 中的每個 ID 添加重要列的值

所以我可以有一個看起來像這樣的 output

select 'Alice' AS ID, [STRUCT('col1' AS column, 1 AS rank, 2 AS value), STRUCT('col4' AS column, 2 AS rank, 0 AS value), STRUCT('col3' AS column, 3 AS rank, 6 AS value)] AS important_columns
union all
select 'Bob' AS ID, [STRUCT('col4' AS column, 1 AS rank, 7 AS value), STRUCT('col2' AS column, 2 AS rank, 4 AS value), STRUCT('col1' AS column, 3 AS rank, 1 AS value)]

output

我希望代碼是動態的，因此即使列名更改或列數更改也能正常工作

Answer 1

考慮以下查詢。

EXECUTE IMMEDIATE FORMAT("""
  CREATE TEMP TABLE sample_data1_unpivoted AS 
  SELECT ID, ARRAY_AGG(STRUCT(column, value)) outputs FROM sample_data1 UNPIVOT (value FOR column IN (%s)) GROUP BY 1
""", ARRAY_TO_STRING(
  REGEXP_EXTRACT_ALL(TO_JSON_STRING((SELECT AS STRUCT * EXCEPT (ID) FROM sample_data1 LIMIT 1)), r'"([^,{]+)":'), ',')
);

SELECT ID, ARRAY (
         SELECT AS STRUCT column, rank, value 
           FROM t1.important_columns LEFT JOIN t2.outputs USING (column)
       ) important_columns
  FROM sample_data2 t1
  LEFT JOIN sample_data1_unpivoted t2 USING (ID);

查詢結果