use month names instead of numbers, in union select mysql - mysql

Question

First, I just used union, and I don't really understand it.
basically, to change the name of the month I usually use
select MONTHNAME (date)
But in this case I dont know Union more deeply so it is very confusing to change the number of months to the name of the month. Can you help me? please don't just give an answer but please also include an explanation.
this my query, and fyi this query was helped by the 'sticky bit' in my previous topic.
SELECT m.month month_table,
coalesce(s.count, 0) cstart,
coalesce(e.count, 0) cend
FROM (SELECT 1 month
UNION ALL
SELECT 2 month
UNION ALL
SELECT 3 month
UNION ALL
SELECT 4 month
UNION ALL
SELECT 5 month
UNION ALL
SELECT 6 month
UNION ALL
SELECT 7 month
UNION ALL
SELECT 8 month
UNION ALL
SELECT 9 month
UNION ALL
SELECT 10 month
UNION ALL
SELECT 11 month
UNION ALL
SELECT 12 month) m
LEFT JOIN (SELECT month(n.start_date) month,
count(*) count
FROM newdata n
GROUP BY month(n.start_date)) s
ON s.month = m.month
LEFT JOIN (SELECT month(n.end_date) month,
count(*) count
FROM newdata n
GROUP BY month(n.end_date)) e
ON e.month = m.month
ORDER BY m.month;
I have tried to replace all 'month' to 'monthname' but the results is 0.
Before i change month to monthname
month_table|cstart|cend
1 | 1 | 0
2 | 0 | 1
3 | 0 | 0
4 | 0 | 0
5 | 0 | 0
6 | 0 | 0
7 | 0 | 0
8 | 1 | 0
9 | 0 | 0
10 | 1 | 2
11 | 0 | 0
12 | 0 | 0
and when i change month to monthname the results be
month_table|cstart|cend
1 | 0 | 0
2 | 0 | 0
3 | 0 | 0
4 | 0 | 0
5 | 0 | 0
6 | 0 | 0
7 | 0 | 0
8 | 0 | 0
9 | 0 | 0
10 | 0 | 0
11 | 0 | 0
12 | 0 | 0

Answer 1

You can just use CONCAT to convert your month number into a date string that you can then pass to MONTHNAME i.e. change the first line of your query to:
SELECT MONTHNAME(CONCAT('2018-', m.month, '-01')) month_table,
Output (for your sample data from your previous question):
month_table cstart cend
January 1 0
February 0 1
March 0 0
April 0 0
May 0 0
June 0 0
July 0 0
August 1 0
September 0 0
October 1 2
November 0 0
December 0 0
SQLFiddle demo

Answer 2

Most people just create look up table for this kind of thing, populate it once then use it. Not only does it perform vastly better, but it’s easily understood and reused.
Another common tick is to create a “calendar” table that contains all the dates within a decade or so, with day names, public holiday indicators, etc, which makes writing queries that output data for each day, even if there is no data for that day, super easy. And it’s completely portable.
Forget the SQL Kung Fu and apply KISS.