# PostgreSQL Subquery: Find the 4th minimum salary of all the salaries

**16.** Write a subquery to find the 4th minimum salary of all the salaries.

**Sample Solution:**

**Code:**

```
-- This SQL query retrieves distinct salary values where each salary is in the bottom 4 distinct salary values in the employees table.
SELECT DISTINCT salary -- Selects distinct salary values from the employees table (aliased as 'e1')
FROM employees e1 -- Specifies the table from which to retrieve data (aliased as 'e1'), in this case, the employees table
WHERE 4 = ( -- Filters the rows to include only those where the count of distinct salary values that are greater than or equal to the salary of the current row is equal to 4
SELECT COUNT(DISTINCT salary) -- Subquery: Counts the distinct salary values that are greater than or equal to the salary of the current row
FROM employees e2 -- Specifies the table from which to retrieve data (aliased as 'e2'), in this case, the employees table
WHERE e1.salary >= e2.salary -- Filters distinct salary values that are greater than or equal to the salary of the current row (aliased as 'e1')
);
```

**Explanation:**

- This SQL query retrieves distinct salary values where each salary is in the bottom 4 distinct salary values in the employees table.
- The outermost SELECT statement retrieves distinct salary values from the employees table (aliased as 'e1').
- The WHERE clause filters the rows to include only those where the count of distinct salary values that are greater than or equal to the salary of the current row is equal to 4.
- The subquery calculates the count of distinct salary values that are greater than or equal to the salary of the current row.

**Sample table: employees**

Output:

pg_exercises=# SELECT DISTINCT salary pg_exercises-# FROM employees e1 pg_exercises-# WHERE 4 = (SELECT COUNT(DISTINCT salary) pg_exercises(# FROM employees e2 pg_exercises(# WHERE e1.salary >= e2.salary); salary --------- 2500.00 (1 row)

## Practice Online

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**Previous: ** Write a subquery to find the 5th maximum salary of all salaries.

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