The scalar function ROWID returns the row identifier of the current row in a table. This function takes no arguments. The ROWID of a row is determined when the row is inserted into the table. Once assigned, the ROWID remains the same for the row until the row is deleted. At any given time, each row in a table is uniquely identified by its ROWID.
Selecting a row in a table using its ROWID is the most efficient way of selecting the row. For example:
WHERE ROWID = '10';