Insert into MySQL table all Sundays and Saturdays from current year - mysql

Question

I have this tiny table with just "fecha" field in it.
I need a MySQL query that inserts every sunday and saturday of the year to the table.
My own research got me to the point where i know i need to do something like this:
DECLARE diaRecorrido date();
SET diaRecorrido = date(now());
WHILE DATEPART(WEEKDAY,diaRecorrido) = 1 or DATEPART(WEEKDAY,diaRecorrido) = 7
BEGIN
INSERT INTO feriados (fecha)
VALUES (diaRecorrido)
IF diaRecorrido=2017/01/01
THEN
LEAVE lazo;
END IF;
END;
Any guidance is much apreciated!

Answer 1

I think, you should use DAYOFWEEK()
create PROCEDURE generateSundayAndSaturday()
BEGIN
DECLARE _now DATETIME;
DECLARE _endYear DATETIME;
SET _endYear = DATE_FORMAT(NOW() + INTERVAL 1 YEAR ,'%Y-01-01');
SELECT now() into _now from dual;
while _now < _endYear DO
if DAYOFWEEK(_now) = 7 THEN -- Saturday
-- insert into
SET _now = _now + INTERVAL 1 DAY;
ELSEIF DAYOFWEEK(_now) = 1 THEN -- Sunday
-- insert into
SET _now = _now + INTERVAL 6 DAY;
ELSE
SET _now = _now + INTERVAL 1 DAY;
END IF;
END WHILE;
END;

Answer 2

You could create a numbers table and then select from it the days of the year which you wish to keep:
DECLARE #Date1 DATE, #Date2 DATE
SET #Date1 = '20160101'
SET #Date2 = '20161231'
INSERT INTO feriados
SELECT DATEADD(DAY,number+1,#Date1) [Date]
FROM master..spt_values
WHERE type = 'P' AND
DATEADD(DAY,number+1,#Date1) < #Date2 AND
(DATEPART(WEEKDAY, DATEADD(DAY,number+1,#Date1)) = 1 OR
DATEPART(WEEKDAY, DATEADD(DAY,number+1,#Date1)) = 7)

Answer 3

This is MS SQL (t-sql) query. I think you can fix small syntax differences for MySQL.
declare #thisYear datetime=cast(year(getdate()) as varchar)+'-01-01',
#newyear datetime=cast(year(getdate())+1 as varchar)+'-01-01'
declare #frstSat datetime, #frstSun datetime
select #frstSat= dateadd(dd,7-DATEPART(weekday,#thisYear),#thisYear) ,
#frstSun= case DATEPART(weekday,#thisYear)
when 1 then #thisYear --if 1/1 is Sunday
else dateadd(dd,8-DATEPART(weekday,#thisYear),#thisYear) end
;with sat as (
select #frstSat dt,'Sat' WkDay
union all
select dateadd(dd,7,dt),'Sat' WkDay
from sat
where dateadd(dd,7,dt)<#newyear
)
,sun as (
select #frstSun dt,'Sun' WkDay
union all
select dateadd(dd,7,dt),'Sun' WkDay
from sun
where dateadd(dd,7,dt)<#newyear
)
--insert mytable
select * from sat
union
select * from sun
order by dt