WITH TIES Clause FAQS

1. What is the WITH TIES clause in Oracle SQL?

• The WITH TIES clause is used in conjunction with the FETCH FIRST or FETCH NEXT clauses to include all rows that have the same value in the ORDER BY column(s) as the last row returned by the query.
• This ensures that if multiple rows share the same value for the column used for sorting, those rows will also be included, even if it results in more rows than the number specified.

Example:

SELECT employee_id, first_name, last_name, salary

FROM employees

ORDER BY salary DESC

FETCH FIRST 5 ROWS WITH TIES;

2. When should I use WITH TIES?

• You should use WITH TIES when you want to return more than the exact number of rows you specify, but only if there are additional rows that tie with the last row of your result set based on the sorting criteria.
• It's ideal when you're dealing with rankings, top N results, or other scenarios where you want to ensure that tied values are included.

Example: If the top 5 employees by salary have two employees tied at the 5th position, WITH TIES ensures that both employees are included.

3. How does WITH TIES work with FETCH FIRST or FETCH NEXT?

• When you use FETCH FIRST or FETCH NEXT, the query will return the specified number of rows.
• However, when WITH TIES is added, the query will also include any rows that share the same value as the last row in the result set based on the ORDER BY clause, potentially returning more rows than the specified limit.

Example:

SELECT * FROM employees

ORDER BY salary DESC

FETCH FIRST 3 ROWS WITH TIES;

• If the 3rd and 4th employees have the same salary, both employees will be included, resulting in 4 rows.

4. What happens if there are no ties?

• If there are no ties (i.e., no rows have the same value in the sorting column as the last row), then WITH TIES behaves the same as FETCH FIRST or FETCH NEXT without WITH TIES.
• It will return the exact number of rows specified.

Example:

SELECT * FROM employees

ORDER BY salary DESC

FETCH FIRST 5 ROWS WITH TIES;

If no two employees have the same salary, it will return exactly 5 rows.

5. Do I always need to use ORDER BY with WITH TIES?

Yes, the ORDER BY clause is required when using WITH TIES. This is because the query needs to know which rows are the "last" in order to determine if there are any tied rows to include.

6. Can I use WITH TIES without ORDER BY?

• No, you cannot use WITH TIES without an ORDER BY clause.
• The concept of "ties" is based on the sorting order, and without an ORDER BY, Oracle would not know how to compare rows for ties.

7. What is the difference between WITH TIES and WITHOUT TIES?

• With WITH TIES: The query will return more rows if any rows tie with the last row returned.
• Without WITH TIES: The query will return exactly the number of rows you specify, even if some rows have the same value as the last row (they will be excluded).

Example:

-- Without `WITH TIES` (only the top 3 rows)

SELECT * FROM employees

ORDER BY salary DESC

FETCH FIRST 3 ROWS ONLY;

-- With `WITH TIES` (may return more than 3 rows if there are ties)

SELECT * FROM employees

ORDER BY salary DESC

FETCH FIRST 3 ROWS WITH TIES;

8. Can I use WITH TIES with OFFSET and FETCH NEXT for pagination?

• Yes, you can use WITH TIES with OFFSET and FETCH NEXT for pagination. This will allow you to paginate through a result set while ensuring that tied rows are included.

Example:

SELECT * FROM employees

ORDER BY salary DESC

OFFSET 10 ROWS FETCH NEXT 5 ROWS WITH TIES;

• This will skip the first 10 rows and fetch the next 5 rows, including any additional rows that tie with the 5th row.

9. Can I use WITH TIES in a JOIN query?

• Yes, you can use WITH TIES in a JOIN query, just like in a simple SELECT statement.
• However, you must ensure that the ORDER BY clause is relevant to the columns you are using for the tie condition.

Example:

SELECT e.employee_id, e.first_name, e.last_name, e.salary, d.department_name

FROM employees e

JOIN departments d ON e.department_id = d.department_id

ORDER BY e.salary DESC

FETCH FIRST 5 ROWS WITH TIES;

10. What happens if the ORDER BY clause involves multiple columns?

• When the ORDER BY clause involves multiple columns, WITH TIES will consider the tie-breaking logic for all the columns in the specified order.
• If two rows have the same value in the first column, Oracle will compare the second column to determine if they should be tied.

Example:

SELECT employee_id, first_name, last_name, salary, department_id

FROM employees

ORDER BY salary DESC, department_id DESC

FETCH FIRST 5 ROWS WITH TIES;

• This query will return the top 5 employees by salary, and if two employees share the same salary, it will check their department IDs to determine if they should be included as tied rows.

11. Does WITH TIES impact performance?

• Using WITH TIES can slightly impact performance because Oracle needs to examine additional rows to check for ties.
• However, the impact is generally minimal unless you're working with a very large result set.
• It's recommended to use it when you need to ensure that tied rows are included, but avoid unnecessary use if performance is a critical concern.

12. What happens if I fetch more rows than expected?

• When you use WITH TIES, you might end up with more rows than the limit you initially specified.
• For example, if you're fetching the first 3 rows but the 3rd row is tied with several others, you might receive more than 3 rows.

Example:

SELECT * FROM employees

ORDER BY salary DESC

FETCH FIRST 3 ROWS WITH TIES;

• If the 3rd and 4th employees have the same salary, both will be included, resulting in 4 rows being returned.

13. Can I use WITH TIES to return all rows with the highest value?

• Yes, you can use WITH TIES to fetch all rows that share the same value as the highest or lowest row, depending on your ORDER BY direction.

Example (Fetching all employees with the highest salary):

SELECT * FROM employees

ORDER BY salary DESC

FETCH FIRST 1 ROWS WITH TIES;

This will return all employees with the highest salary, even if there are more than one.

14. Can I use WITH TIES with GROUP BY?

• Yes, you can use WITH TIES with a GROUP BY clause.
• The rows returned will be based on the result of the aggregation, and WITH TIES will ensure that any rows tied with the last row in the result set are included.

Example:

SELECT department_id, MAX(salary) AS max_salary

FROM employees

GROUP BY department_id

ORDER BY max_salary DESC

FETCH FIRST 3 ROWS WITH TIES;

• This query will return the top 3 departments by the highest salary, including any departments with the same salary as the 3rd department.