It looks like you're trying to create a SQL case statement that checks for null values in the `MNTH_END_STK_VAL_STK` field and also looks at specific conditions based on the `CURRENT_DATE`. The syntax you provided has a few issues that may prevent it from working correctly in SAP DataSphere.
Here's the revised SQL case statement that should work in SAP DataSphere:
```sql
CASE
WHEN
CONCAT(MNTH_END_STK_FSCL_YR,