Question

In SQL, the aggregate function which will display the cardinality of the table is \(\_\_\_\_\_\). 
 

• A. sum()
• B. count(*)
• C. avg()
• D. sum(*)

Hint:

Use count(*) when you need to determine the total number of rows in a table, regardless of whether they contain NULL values or not.

Answer 1

The Correct Option is B

In SQL, the count(*) function is used to count the number of rows in a table, which effectively gives the cardinality of the table. Other functions like sum() and avg() are used for numerical aggregations, not for counting rows.