Create a Cumulative Sum Column in MySQL

Question

I have a table that looks like this   id   count 1    100 2    50 3    10   I want to add a new column called cumulative sum  so the table would look like this   id   count  cumulative sum 1    100    100 2    50     150 3    10     160   Is there a MySQL update statement that can do this easily  What s the best way to accomplish this

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select t1 id  t1 count  SUM t2 count  cumulative sum     from table t1          join table t2 on t1 id  gt   t2 id     group by t1 id  t1 count   Step by step   1- Given the following table   select   from table t1  order by t1 id   id    count  1     11  2     12     3     13   2 - Get information by groups  select   from table t1      join table t2 on t1 id  gt   t2 id order by t1 id  t2 id   id    count   id   count  1    11      1     11   2    12      1     11  2    12      2     12   3    13      1     11  3    13      2     12  3    13      3     13   3- Step 3  Sum all count by t1 id group  select t1 id  t1 count  SUM t2 count  cumulative sum from table t1      join table t2 on t1 id  gt   t2 id group by t1 id  t1 count    id    count   cumulative sum  1     11        11  2     12        23  3     13        36

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If performance is an issue  you could use a MySQL variable   set  csum    0  update YourTable set cumulative sum     csum     csum   count  order by id    Alternatively  you could remove the cumulative sum column and calculate it on each query   set  csum    0  select id  count    csum     csum   count  as cumulative sum from YourTable order by id    This calculates the running sum in a running way

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Using a correlated query       SELECT t id           t count            SELECT SUM x count              FROM TABLE x            WHERE x id  lt   t id  AS cumulative sum     FROM TABLE t ORDER BY t id   Using MySQL variables       SELECT t id           t count            running total     running total   t count AS cumulative sum     FROM TABLE t     JOIN  SELECT  running total    0  r ORDER BY t id   Note    The JOIN  SELECT  running total    0  r is a cross join  and allows for variable declaration without requiring a separate SET command    The table alias  r  is required by MySQL for any subquery derived table inline view    Caveats    MySQL specific  not portable to other databases The ORDER BY is important  it ensures the order matches the OP and can have larger implications for more complicated variable usage  IE  psuedo ROW NUMBER RANK functionality  which MySQL lacks

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MySQL 8 0 MariaDB supports windowed SUM col  OVER     SELECT    SUM cnt  OVER ORDER BY id  AS cumulative sum FROM tab    Output    -----------------------------     id     cnt     cumulative sum     ----- ------ ----------------       1     100                100        2      50                150        3      10                160     -----------------------------    db lt  fiddle

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Sample query   SET  runtot  0  SELECT    q1 d     q1 c       runtot     runtot   q1 c  AS rt FROM     SELECT        DAYOFYEAR date  AS d         COUNT    AS c     FROM  orders     WHERE  hasPaid  gt  0     GROUP  BY d     ORDER  BY d  AS q1

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select Id  Count   total     total   Count as cumulative sum from YourTable   Select  total    0  as total

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UPDATE t SET cumulative sum      SELECT SUM x count   FROM t x  WHERE x id  lt   t id

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You could also create a trigger that will calculate the sum before each insert   delimiter    CREATE TRIGGER calCumluativeSum  BEFORE INSERT ON someTable   FOR EACH ROW BEGIN    SET cumulative sum          SELECT SUM x count          FROM someTable x         WHERE x id  lt   NEW id            set  NEW cumulative sum   cumulative sum    END      I have not tested this

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select id count sum count over order by count desc  as cumulative sum from tableName   I have used the sum aggregate function on the count column and then used the over clause  It sums up each one of the rows individually  The first row is just going to be 100  The second row is going to be 100 50  The third row is 100 50 10 and so forth  So basically every row is the sum of it and all the previous rows and the very last one is the sum of all the rows  So the way to look at this is each row is the sum of the amount where the ID is less than or equal to itself

[mysql] Create a Cumulative Sum Column in MySQL

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