Return the phone numbers of employees with salaries between 8000 and 12000.
SELECT phone_number FROM employees WHERE salary BETWEEN 8000 AND 12000
``` yaml
employees: # name of dataframe
- EMPLOYEE_ID:
    dtype: int64
    sample_values: 100, 101, 102
- FIRST_NAME:
    dtype: string
    sample_values: Steven, Neena, Lex
- LAST_NAME:
    dtype: string
    sample_values: King, Kochhar, De Haan
- EMAIL:
    dtype: string
    sample_values: SKING, NKOCHHAR, LDEHAAN
- PHONE_NUMBER:
    dtype: string
    sample_values: 515.123.4567, 515.123.4568, 515.123.4569
- HIRE_DATE:
    dtype: datetime
    sample_values: 1987-06-17, 1987-06-18, 1987-06-19
- JOB_ID:
    dtype: string
    sample_values: AD_PRES, AD_VP, AD_VP
- SALARY:
    dtype: int64
    sample_values: 24000, 17000, 17000
- COMMISSION_PCT:
    dtype: float64
    sample_values: 0.0, 0.0, 0.0
- MANAGER_ID:
    dtype: int64
    sample_values: 0, 100, 100
- DEPARTMENT_ID:
    dtype: int64
    sample_values: 90, 90, 90

```
PHONE_NUMBER
590.423.4567
515.124.4569
515.124.4169
515.124.4269
515.127.4561
650.123.1234
650.123.2234
011.44.1344.429278
011.44.1344.619268
011.44.1344.429018
011.44.1344.129268
011.44.1344.345268
011.44.1344.478968
011.44.1344.498718
011.44.1345.429268
011.44.1345.929268
011.44.1345.829268
011.44.1345.729268
011.44.1346.129268
011.44.1346.229268
011.44.1343.929268
011.44.1343.829268
011.44.1343.729268
011.44.1644.429267
011.44.1644.429266
011.44.1644.429265
011.44.1644.429264
515.123.8888
515.123.8080
515.123.8181
