UPDATE with SUM() in MySQL

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My table:

ID  NAME COST  PAR  P_val  S_val
1   X    5     0    1      0
1   y    5     0    2      0
1   z    5     0    0      5
2   XY   4     0    4      4

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抹茶落季

2020-12-11 06:49

UPDATE Table_Name SET PAR = (SELECT SUM(S_val) FROM Table_Name WHERE ID=1) 
FROM   Table_Name

Check writing. delete "FROM Table_Name" row.

TRUE command is:

UPDATE Table_Name SET PAR = (SELECT SUM(S_val) FROM Table_Name WHERE ID=1)

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梦毁少年i

2020-12-11 06:54

Try:

UPDATE Table_NAme SET PAR= summedValue
FROM   TAble_NAME t
JOIN (
  SELECT ID, SUM(S_val) as summedvalue 
  FROM TABLE_NAME GROUP BY ID
  ) s on t.ID = s.ID

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闹比i

2020-12-11 07:14

Unfortunately, you cannot update a table joined with itself in MySQL.

You'll need to create a function as a workaround:

DELIMITER $$

CREATE FUNCTION `fn_get_sum`(_id INT) RETURNS int(11)
READS SQL DATA
BEGIN
      DECLARE r INT;
      SELECT  SUM(s_val)
      INTO    r
      FROM    table_name
      WHERE   id = _id;
      RETURN r;
END $$

DELIMITER ;

UPDATE  table_name
SET     par = fn_get_sum(id)

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