MySQL Date and Time Exercises: Get the distinct Mondays from hire_date in employees tables
MySQL Date Time: Exercise-3 with Solution
Write a MySQL query to get the distinct Mondays from hire_date in employees tables.
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 | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+
Code:
-- This SQL query retrieves distinct dates representing the first day of the week for each hire date in the 'employees' table.
SELECT DISTINCT( -- Selects distinct values of the result set.
STR_TO_DATE( -- Converts a string into a date value.
CONCAT( -- Concatenates multiple strings into one string.
YEARWEEK(hire_date), -- Gets the year and week number for each hire date.
'1' -- Appends '1' to the end of the concatenated string.
),
'%x%v%w' -- Specifies the format of the input string.
)
)
FROM
employees; -- Specifies the 'employees' table.
Explanation:
- The YEARWEEK() function returns the year and week number for a given date.
- CONCAT() concatenates the year and week number with '1'.
- %x%v%w represents the format for the input string: %x for the year, %v for the week (ISO 8601 week), and %w for the day of the week.
- STR_TO_DATE() converts the concatenated string into a date value based on the specified format.
- The SELECT DISTINCT() statement ensures that only unique dates are returned.
- The query produces a distinct set of dates representing the first day of the week for each hire date in the 'employees' table.
Pictorial Presentation of the above query:
Sample Output:
(STR_TO_DATE (CONCAT(YEARWEEK(hire_date),'1'),'%x%v%w')) 1987-06-08T04:00:00.000Z 1987-06-15T04:00:00.000Z 1987-06-22T04:00:00.000Z 1987-06-29T04:00:00.000Z 1987-07-06T04:00:00.000Z 1987-07-13T04:00:00.000Z 1987-07-20T04:00:00.000Z 1987-07-27T04:00:00.000Z 1987-08-03T04:00:00.000Z 1987-08-10T04:00:00.000Z 1987-08-17T04:00:00.000Z 1987-08-24T04:00:00.000Z 1987-08-31T04:00:00.000Z 1987-09-07T04:00:00.000Z 1987-09-14T04:00:00.000Z 1987-09-21T04:00:00.000Z
Go to:
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MySQL Code Editor:
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