SQL更新左连在一起，其中where子句

Question

have a question about an SQL join. I would like to update a table that runs within a program for a value calculation based on the price development of different accounts (eg price development of coal, leather, etc.). In the current version these are about 3000 accounts with an ID, a unique GP number and a value for each year. The problem is that with the new release of the GP values about 900 accounts have been dropped. However, the program must be able to calculate further with these values, since the calculations were assigned to the IDs and not to the GP values. I want to update the GP values for the years 2015, 2016 and 2017...However I don't know how to do it without shooting the IDs (values that are not updated and for which there are calculations will simply get the general price development, but this update can be neglected)

So the first table looks like this:

INSERT INTO `gps` (`id`, `Nummer`, `Beschreibung`, `Basisjahr`, `depricated`, `1949`, `1950`, `1951`, `1952`, `1953`, `1954`, `1955`, `1956`, `1957`, `1958`, `1959`, `1960`, `1961`, `1962`, `1963`, `1964`, `1965`, `1966`, `1967`, `1968`, `1969`, `1970`, `1971`, `1972`, `1973`, `1974`, `1975`, `1976`, `1977`, `1978`, `1979`, `1980`, `1981`, `1982`, `1983`, `1984`, `1985`, `1986`, `1987`, `1988`, `1989`, `1990`, `1991`, `1992`, `1993`, `1994`, `1995`, `1996`, `1997`, `1998`, `1999`, `2000`, `2001`, `2002`, `2003`, `2004`, `2005`, `2006`, `2007`, `2008`, `2009`, `2010`, `2011`, `2012`, `2013`, `2014`, `2015`, `2016`, `2017`, `2018`, `2019`, `created_at`, `updated_at`) VALUES 
(1, 'GP09-05', 'Kohle', 0, 0, '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '100.0', '109.9', '113.0', '114.1', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0000-00-00 00:00:00', '0000-00-00 00:00:00'), 
(2, 'GP09-06', 'Erdöl und Erdgas', 0, 0, '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '26.2', '27.8', '32.9', '31.0', '30.0', '45.5', '57.5', '52.0', '58.8', '55.0', '75.3', '96.4', '89.8', '113.9', '81.3', '100.0', '118.2', '142.2', '143.4', '0.0', '0.0', '0.0', '0.0', '0.0', '0.0', '0000-00-00 00:00:00', '0000-00-00 00:00:00'),

And so on (3000 datasets)

The second table, which i wanna join, looks like this(database looks like this: "gps_neu.gps"):

INSERT INTO `gps` (`Nummer`, `2014`, `2015`, `2016`,`2017`) VALUES 
('GP09-052010', '113', '111.3', '110.7','108'), 
('GP09-061010', '130.7', '79.5', '62', '81.1')

The DB looks like this: First: gps.gps.1949 and so on. Second: gps_neu.gps.2014 and so on.

My current code looks like this:

SELECT gps.2014,
       gps.2015,
       gps.2016,
       gps.2017
  FROM gps.gps
  JOIN LEFT gps_neu.gps.2014,
        gps_neu.gps.2015,
        gps_neu.gps.2016,
        gps_neu.gps.2017
    ON gps.gps.Nummer = gps_neu.gps.Nummer;

Hope someone can help me to fix it.

Answer 1

After understanding your problem i think you don't need left join just need an update with inner join

update  gps.gps
  set gps.2014 = gps_neu.gps.2014 ,
   gps.2015 = gps_neu.gps.2014,
   gps.2016 = gps_neu.gps.2014,
   gps.2017 = gps_neu.gps.2014
FROM gps.gps
INNER JOIN gps_neu 
ON gps.gps.Nummer = gps_neu.gps.Nummer;

Answer 2

I think what you're looking for is IFNULL() in the SELECT list.

SELECT 
    IFNULL(gps.gps.2014, gps_neu.gps.2014) AS `2014`,
    IFNULL(gps.gps.2015, gps_neu.gps.2015) AS `2015`,
    IFNULL(gps.gps.2016, gps_neu.gps.2016) AS `2016`,
    IFNULL(gps.gps.2017, gps_neu.gps.2017) AS `2017`
FROM gps.gps
LEFT JOIN gps_neu.gps
ON gps.gps.Nummer = gps_neu.gps.Nummer;