我分解了一个嵌套模式，但是没有得到想要的东西，
爆炸前看起来像这样：
df.show（）
+----------+----------------------------------------------------------+
|CaseNumber| SourceId |
+----------+----------------------------------------------------------+
| 0 |[{"id":"1","type":"Sku"},{"id":"22","type":"ContractID"}] |
+----------|----------------------------------------------------------|
| 1 |[{"id":"3","type":"Sku"},{"id":"24","type":"ContractID"}] |
+---------------------------------------------------------------------+
我希望它像这样
+----------+-------------------+
| CaseNumber| Sku | ContractId |
+----------+-------------------+
| 0 | 1 | 22 |
+----------|------|------------|
| 1 | 3 | 24 |
+------------------------------|