SQL | With Ties Clause

The WITH TIES clause in SQL is used in conjunction with the SELECT TOP clause (primarily in SQL Server) to return any additional rows that tie with the last row in the result set based on the ORDER BY criteria.

When you use SELECT TOP n with ORDER BY, you usually get the first n rows according to the sort order specified. But, if the nth row has ties (i.e., there are rows with the same values as the nth row based on the ORDER BY columns), the WITH TIES option will include all of these tied rows, even if it exceeds the n value you specified.

Example:

Consider a table Students with the following data:

| ID | Name  | Marks |
|----|-------|-------|
| 1  | Alice | 90    |
| 2  | Bob   | 88    |
| 3  | Carol | 90    |
| 4  | David | 85    |
| 5  | Eve   | 88    |

If you want to select the top 2 students based on marks, you might use:

SELECT TOP 2 Name, Marks 
FROM Students 
ORDER BY Marks DESC;

This will return:

| Name  | Marks |
|-------|-------|
| Alice | 90    |
| Carol | 90    |

However, if you want to get the top 2 students and any students who tied with the 2nd student based on the marks, you can use WITH TIES:

SELECT TOP 2 Name, Marks 
FROM Students 
ORDER BY Marks DESC 
WITH TIES;

This will return:

| Name  | Marks |
|-------|-------|
| Alice | 90    |
| Carol | 90    |
| Bob   | 88    |
| Eve   | 88    |

Notice how Bob and Eve are also returned even though we specified TOP 2, because they tied with the second highest marks.

Caveats:

Always use WITH TIES with an ORDER BY clause. If not, the result can be unpredictable.
When using WITH TIES, the actual number of returned rows might exceed the number specified in the TOP clause due to tied values. Make sure you're okay with this behavior before using it.
Not all database systems support WITH TIES. It's mostly associated with SQL Server. Always refer to the documentation of the specific RDBMS you are using.

How to use WITH TIES in SQL:
- WITH TIES is used to include additional rows with the same sort key values as the last row in the result set.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```
Retrieving additional rows with ties in SQL queries:
- WITH TIES ensures that rows with the same sort key values as the last row are included in the result set.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```
Using ORDER BY with WITH TIES in SQL:
- The ORDER BY clause is crucial when using WITH TIES to determine the sorting of rows.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```

Alternative approaches to WITH TIES in SQL:

Alternatives include using window functions or subqueries to achieve similar results.

SELECT column1, column2
FROM (
   SELECT column1, column2, ROW_NUMBER() OVER (ORDER BY column1 DESC) AS row_num
   FROM example_table
) AS numbered_rows
WHERE row_num <= 5;

Limiting results with WITH TIES in SQL Server:
- WITH TIES can be combined with TOP to limit the number of rows returned.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```
Combining TOP and WITH TIES in SQL queries:
- TOP and WITH TIES can be used together to limit the result set and include ties.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```
Handling NULL values with WITH TIES in SQL:
- WITH TIES operates on the sorted result set, including NULL values.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```
Use cases for WITH TIES in SQL:
- WITH TIES is useful when you want to retrieve additional rows with the same sort key values.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```

WITH TIES vs. traditional pagination in SQL:

WITH TIES is different from traditional pagination, as it includes additional rows with ties.

-- Traditional Pagination
SELECT column1, column2
FROM example_table
ORDER BY column1
OFFSET 0 ROWS
FETCH NEXT 5 ROWS ONLY;

-- WITH TIES
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1;

Limitations and caveats of WITH TIES:
- WITH TIES may have performance implications, and the result set may vary based on the database system.
```
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;
```

Compatibility of WITH TIES across different databases:

WITH TIES is supported in SQL Server, but its usage may vary across different database systems.

-- SQL Server
SELECT TOP 5 WITH TIES column1, column2
FROM example_table
ORDER BY column1 DESC;

-- MySQL
-- (Use LIMIT with a subquery or alternative approaches)

WITH TIES in subqueries in SQL:

WITH TIES can be used in subqueries to achieve the desired result set.

SELECT *
FROM (
   SELECT TOP 5 WITH TIES column1, column2
   FROM example_table
   ORDER BY column1 DESC
) AS subquery_result;