Hi @Anonymous,
The trigger "When an Item has been modified" is not supported in microsoft flow currently,
Please make sure you have a column value in sharepoint list the same as a column value in sql server connector.
For example, you have a Title column in the in sharepoint list, when an item is created in the sharepoint list, the item would be created in the sql server with the same Title.
I have made a test on my side to sync excel table from a sharepoint list when an item is created or when an item is modified, you could refer to my flow to create your flow to sync SQL server from a sharepoint list.
The screenshot of the flow as below:


Best regards,
Alice