Question at position 45 COUNT(*) tallies only those rows that contain a value, while COUNT counts all rows.TrueFalse

Question

BlackTom AI · Accepted Answer

Here is the evaluation of each choice based on the statement given and how COUNT and COUNT(*) actually behave.
Option 1: 'True' — This would claim that COUNT(*) tallies only those rows that contain a value, and that COUNT tallies all rows. In reality, COUNT(*) counts every row in the result set, regardless of whether any columns contain null values. It does not require any column to have a non-null value. So this option misstates the behavior of COUNT(*).
Option 2: 'False' — This correctly states that COUNT(*) tallies all rows in the result set, whereas COUNT (typically used as COUNT(column) or COUNT(expression)) counts only the rows where the specified column or expression evaluates to a non-null value. If a column has nulls, those rows are not counted by COUNT(column). This aligns with standard SQL semantics and clarifies the common confusion between the two forms.
Additional nuance: if you write COUNT(*) vs COUNT(*) over a filtered set, the counts reflect the rows present after filtering; but the key distinction remains that COUNT(*) includes all rows, while COUNT(column) excludes rows where column is null. When using COUNT(*) and COUNT(1) or COUNT(*) with a constant expression, the results are effectively the same since the expression is never null.
In summary, the statement is false because COUNT(*) does not require a value in any column, and COUNT only counts non-null occurrences of the specified column or expression.

Question at position 45 COUNT(*) tallies only those rows that contain a value, while COUNT counts all rows.TrueFalse

View Explanation

Log in for full answers

Similar Questions

Question at position 50 COUNT(*) tallies only those rows that contain a value, while COUNT counts all rows.TrueFalse

Question at position 43 COUNT(*) tallies only those rows that contain a value, while COUNT counts all rows.TrueFalse

Question at position 37 COUNT(*) tallies only those rows that contain a value, while COUNT counts all rows.TrueFalse

Consider the Student Relation: Student(StudentID, Name, Cohort, Gender).What does the following query return? select count(StudentID) from Student where Cohort = 'C';

What is the result of the following query? `SELECT COUNT(*) FROM employees WHERE salary > 5000;`

More Practical Tools for Students Powered by AI Study Helper

Homework AI Solver

Stylized AI Paper Writer

Plagiarism Checker Assistant

Citation AI Academic Writing Tool

In-Class Translation Assistant

AI Note Generator

AI Quiz Answers

Past Exam Questions from University Test Bank

Smart Practice Assistant

Adaptive Practice

Making Your Study Simpler