Question

我试图将数组值解除到BigQuery / PSQL中的不同行。

这就是我现在所拥有的::

select 
  ';' + convert(varchar, emp_id),
  ';' + convert(varchar, emp_dob),
  ';' + emp_ssid
from ...

我想转换它，如下面BigQuery中所示。

Col_1                    col_2
A                      array: {1,2,3,4,5}

B                      array: {1,2,3}

C                      array: {4,5,6}

Answer 1

使用standard SQL（取消选中“显示选项”下的“使用旧版SQL”框），您可以执行以下操作：

WITH MyTable AS (
  SELECT 'A' AS Col_1, [1, 2, 3, 4, 5] AS col_2
  UNION ALL SELECT 'B', [1, 2, 3]
  UNION ALL SELECT 'C', [4, 5, 6])
SELECT Col_1, col_2 FROM MyTable t, t.col_2;
+-------+-------+
| Col_1 | col_2 |
+-------+-------+
| A     |     1 |
| A     |     2 |
| A     |     3 |
| A     |     4 |
| A     |     5 |
| B     |     1 |
| B     |     2 |
| B     |     3 |
| C     |     4 |
| C     |     5 |
| C     |     6 |
+-------+-------+

这里“逗号”运算符相当于交叉连接，它具有使重复变平的效果。正如Pavan在上面指出的那样，您也可以使用FLATTEN运算符在遗留SQL中完成此操作，尽管语法不同。

Answer 2

如果您受BigQuery Legacy SQL的约束 - 请尝试以下

SELECT col_1, SPLIT(REPLACE(REPLACE(SPLIT(col_2, ':'), '{', ''), '}', ''), ',') AS elem 
FROM
  (SELECT 'A' AS col_1, 'array: {1,2,3,4,5}' AS col_2),
  (SELECT 'B' AS col_1, 'array: {1,2,3}' AS col_2),
  (SELECT 'C' AS col_1, 'array: {4,5,6}' AS col_2)
HAVING elem <> 'array'  

col_1   elem     
A       1    
A       2    
A       3    
A       4    
A       5    
B       1    
B       2    
B       3    
C       4    
C       5    
C       6

在BigQuery / SQL中展开数组值

2 个答案: