select statement that gives a range of dates without any table? - mysql

Question

If I have a MySQL database with ZERO tables in it. Is there an SQL statement that can return results like:
+------------+
| date |
+------------+
| 2017-06-01 |
| 2017-06-02 |
| 2017-06-03 |
| 2017-06-04 |
etc.... to any end date I want
+------------+
The reason I want this is because I want to be able to generate a table like this on the fly to help me with some queries in a different database.

Answer 1

In MariaDB, you can use a built-in seq table to do this. This query, for example, returns the 100 days starting at 1-Nov-2017
SELECT '2017-11-01' + INTERVAL seq.seq DAY AS sequential_day FROM seq_0_to_99 seq
In MySQL, you need to engage in some monkey business to get a sequence of numbers with no tables. This ugly little query generates the numbers from zero to 15,625.
SELECT A.N + 5*(B.N + 5*(C.N + 5*(D.N + 5*(E.N + 5*(F.N))))) AS seq
FROM (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS A
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS B
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS C
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS D
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS E
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS F
You can use it as a subquery to generate a sequence of dates.
select '2017-11-01' + INTERVAL seq.seq DAY AS sequential_day
from (
SELECT A.N + 5*(B.N + 5*(C.N + 5*(D.N + 5*(E.N + 5*(F.N))))) AS seq
FROM (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS A
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS B
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS C
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS D
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS E
JOIN (SELECT 0 AS N UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4) AS F
) AS seq
where seq.seq <= 99
It's not very elegant. It fact, it's ugly. But it works fine.
Or you can make yourself a date table and use it.

Answer 2

I think you can do it via Stored Procedures and Inline Tables
drop procedure if exists timer;
CREATE PROCEDURE timer()
BEGIN
DECLARE i INT DEFAULT 1;
declare d date default now();
drop table B;
create table B (id date);
WHILE (d<='2017-11-23') DO
insert into B values(d);
set d = CURRENT_DATE()+i;
set i = i+1;
END WHILE;
select * from B;
END;
And call this SP when you need such that CALL timer();
NOTE I am not expert in MYSQL and I depend on those answers to compose this answers (: so you can also benefit from, compare dates in mysql, Inline tables in mysql, MySQL functions, and also While Loops
Also Note you can use IN parameter for a target date in the stored procedure

Answer 3

You can use subquery to declare the first date and then increment it, like following:
SELECT #date := DATE_ADD(#date, INTERVAL 1 DAY) AS dates
FROM mysql.help_relation , (
SELECT #date:= DATE_SUB('2017-06-01', INTERVAL 1 DAY)) d
WHERE #date BETWEEN #date AND DATE_SUB('2017-06-04', INTERVAL 1 DAY
);

Answer 4

One method is to create a loop and insert. Note I'm not keen on using "date" as a column name as it gets way too confusing in queries. Also suggest the date is used as primary key.
delimiter \\
## Create the calendar table.
CREATE TABLE calendar (
cal_date date primary key
);
\\
## accepts a date range
CREATE PROCEDURE create_calendar(IN startdate date, IN enddate date)
BEGIN
SET #x = 0;
WHILE (startdate + INTERVAL #x DAY) < enddate DO
## Insert another row
INSERT INTO calendar (cal_date) VALUES (startdate + INTERVAL #x DAY);
SET #x = #x + 1;
END WHILE;
END
\\
## populate the calendar table with wanted range
## nb the enddate is NOT included in the table
CALL create_calendar('2017-01-01','2017-02-01');
\\
select * from calendar;
\\
When you need more dates in the table, re-run the procedure with the wanted range (but those dates must not already exist in the calendar table).
Derived from How to Create a Tally Table in MySQL