Which three are valid SQL commands? (Choose three.)

The three valid SQL commands among the options provided are:

1. SELECT: This command is used to select data from a database. It retrieves data from one or more tables.
2. UPDATE: This command is used to update existing data within a table in a database.
3. ALTER: This command is used to modify the structure of a database. This could include adding, deleting, or modifying columns in a table.

“DESTROY” and “MODIFY” are not standard SQL commands. “MODIFY” might be confused with “ALTER TABLE… MODIFY”, which is a clause used in some SQL dialects (like MySQL) to change a column in a table, but on its own, “MODIFY” is not a standard SQL command.