Hello @Suraj Pawar Vadeghar ,
welcome to this moderated Azure community forum.
You are using the VS code extension for Azure Stream Analytics.
These projects are organized as folders so you need to open the complete folder, not just the script file.
Please test if the extension works as expected.
If this does not work as expected, submit an issue in GitHub so that team can take a look.
If the response helped, do "Accept Answer". If it doesn't work, please let us know the progress. All community members with similar issues will benefit by doing so. Your contribution is highly appreciated.