Sometimes the expression "select count(*)" will return fewer rows than the expression "select count(value)".
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True
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False
To solve this question, one needs to understand the difference between count(*) and count(column_name).
count(*) returns the total number of rows in the table, whereas count(column_name) returns the number of non-null values for the given column.
Now, let's go through each option and explain why it is right or wrong:
A. True: This option is false. count(*) will always return the same value as the number of rows in the table, while count(column_name) will return the number of non-null values for the given column. Thus, it is possible for count(column_name) to return a higher value than count(*), but not a lower value.
B. False: This option is correct. count(*) returns the total number of rows in the table, whereas count(column_name) returns the number of non-null values for the given column. Thus, it is not possible for count(column_name) to return fewer rows than count(*).
The Answer is: B
False is correct. COUNT() counts every row in the result set regardless of NULL values, while COUNT(value) counts only rows where that specific column is non-NULL. Therefore COUNT() is always greater than or equal to COUNT(value) for the same query — it can never return a smaller count. The statement's claim (that COUNT(*) would sometimes be fewer) has the relationship backwards, so it is correctly marked False.