Besides holding more than 1 million rows, what are the main advantages of SQL databases compared to Google spreadsheets?

Question

what projects are best suited for Google spreadsheets and which for SQL?

Answer 1

Well, there are many but here are some of them. Database, support and give you data manipulation at greater hight then spreadsheet. Moreover,
Access to a spreadsheet is sometimes limited to one person at a time. With database management systems, however, several people can access the same data set. Such systems manage editing of data so that two people cannot alter the same data values at the same time. This preserves data integrity, which is harder to manage when using spreadsheets. Output and presentation varies in spreadsheets and databases. With a spreadsheet, you can generate charts and graphs using automated software tools. With a database, such output options are normally a matter for the application providing access to the data. 

Most important is that, you can internally change SQL database structure. But not in spreadsheet.