Computer Science for IGCSE & O level - Databases (Section 4 - No. 31)
What does the `COUNT(*)` function typically return in SQL?
The number of unique values in a column.
The number of rows that meet a certain criteria.
The sum of all the values in a specific column.
All the data from the table.
Giải thích
`COUNT(*)` returns the number of rows in the table or that meet a given criteria specified by the `WHERE` clause.