PostgreSQL String() Function: Extract the last four characters of phone numbers
9. Write a query to extract the last four characters of phone numbers.
Sample Solution:
Code:
-- This SQL query retrieves the last 4 digits of the phone numbers of employees and labels the column as "Ph.No.".
SELECT RIGHT(phone_number, 4) as "Ph.No." -- Retrieves the last 4 digits of the phone numbers and labels the column as "Ph.No."
FROM employees; -- Specifies the table from which to retrieve data, in this case, the employees table
Explanation:
- This SQL query extracts the last 4 digits of the phone numbers of employees.
- The SELECT statement selects the last 4 digits of the phone numbers and labels the column as "Ph.No.".
- The RIGHT() function is used to extract the rightmost 4 characters from the phone_number column.
- The phone_number column is assumed to store phone numbers.
- The result set will contain one column labeled as "Ph.No." with the last 4 digits of the phone numbers for each employee in the employees table.
Sample table: employees
+-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+ | EMPLOYEE_ID | FIRST_NAME | LAST_NAME | EMAIL | PHONE_NUMBER | HIRE_DATE | JOB_ID | SALARY | COMMISSION_PCT | MANAGER_ID | DEPARTMENT_ID | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+ | 100 | Steven | King | SKING | 515.123.4567 | 1987-06-17 | AD_PRES | 24000.00 | 0.00 | 0 | 90 | | 101 | Neena | Kochhar | NKOCHHAR | 515.123.4568 | 1987-06-18 | AD_VP | 17000.00 | 0.00 | 100 | 90 | | 102 | Lex | De Haan | LDEHAAN | 515.123.4569 | 1987-06-19 | AD_VP | 17000.00 | 0.00 | 100 | 90 | | 103 | Alexander | Hunold | AHUNOLD | 590.423.4567 | 1987-06-20 | IT_PROG | 9000.00 | 0.00 | 102 | 60 | | 104 | Bruce | Ernst | BERNST | 590.423.4568 | 1987-06-21 | IT_PROG | 6000.00 | 0.00 | 103 | 60 | | 105 | David | Austin | DAUSTIN | 590.423.4569 | 1987-06-22 | IT_PROG | 4800.00 | 0.00 | 103 | 60 | | 106 | Valli | Pataballa | VPATABAL | 590.423.4560 | 1987-06-23 | IT_PROG | 4800.00 | 0.00 | 103 | 60 | | 107 | Diana | Lorentz | DLORENTZ | 590.423.5567 | 1987-06-24 | IT_PROG | 4200.00 | 0.00 | 103 | 60 | | 108 | Nancy | Greenberg | NGREENBE | 515.124.4569 | 1987-06-25 | FI_MGR | 12000.00 | 0.00 | 101 | 100 | .......... | 206 | William | Gietz | WGIETZ | 515.123.8181 | 1987-10-01 | AC_ACCOUNT | 8300.00 | 0.00 | 205 | 110 | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+
Output:
pg_exercises=# SELECT RIGHT(phone_number, 4) as "Ph.No." pg_exercises-# FROM employees; Ph.No. -------- 4567 4568 4569 4560 5567 4561 4562 4563 4564 4567 4568 4565 4566 1934 1834 1734 1634 2034 2019 1834 8009 ... 7777 8888 8080 8181 (106 rows)
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