SQL Error: ambiguous column nameor syntax error [closed] - sql

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Tried to change my code many times, need help with these errors, please!
Result: ambiguous column name: main.Guides.Guide_ID
SELECT *
FROM Guides
INNER JOIN Guides ON Guides_Countries.Guide_ID = Guides_Countries.Guide_ID
INNER JOIN Countries ON Countries.Country_ID = Guides_Countries.Country_ID
INNER JOIN Guides_Languages ON Guides.Guide_ID = Guides_Languages.Guide_ID
INNER JOIN Languages ON Languages.Language_ID = Guides_Languages.Language_ID
WHERE Countries.Name="Kazakhstan" AND (Languages.Name="German" OR Languages.Name="English") AND Guides.Guide_ID NOT IN
(SELECT Guide_ID
FROM GuidesUnavailableDates
INNER JOIN GuidesUnavailableDates ON GuidesUnavailableDates.UnDate_G_ID=Guides_UnDate.UnDate_G_ID
WHERE (Start_date<="21/06/2020" and End_date>="21/06/2020")
OR (Start_date<="30/06/2020" and End_date>="30/06/2020")
OR (Start_date>="21/06/2020" and End_date<="30/06/2020")
)
;

Answer 1

You have multiple table names appearing multiple times in your FROM clauses. That is causing your problem. I think you want:
SELECT *
FROM Guides g JOIN
Guides_Countries gc
ON gc.Guide_ID = g.Guide_ID JOIN
Countries c
ON c.Country_ID = gc.Country_ID JOIN
Guides_Languages gl
ON g.Guide_ID = gl.Guide_ID JOIN
Languages l
ON l.Language_ID = gl.Language_ID
WHERE c.Name = 'Kazakhstan' AND
l.Name IN ('German', 'English') AND
g.Guide_ID NOT IN (SELECT gud.Guide_ID
FROM GuidesUnavailableDates gud
WHERE gud.Start_date <= '2020-06-30' AND
gud.End_date >= '2020-06-21'
);
Notes:
Guide_Countries is not in your FROM list although Guides is there twice.
IN is much simpler than mutiple ORs.
All columns are qualified so it is clear what table they are coming from.
All tables have simple table aliases which are abbreviations for the table names.
There is no need for a JOIN in the subquery.
Use well formatted dates.
I am guessing that the weird date logic is to find an overlap with the time period mentioned so I simplified the logic. (You haven't explained the logic, so this is a guess and your original code doesn't make sense.)
I strongly recommend using NOT EXISTS with subqueries rather than NOT IN. However, I did not change the code here (mostly because I can't really tell what the subquery is supposed to be doing).