doubu1970 2015-06-14 06:43
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多维数组中的求和值(选择多行的多个列)

Let's say I have 5 different columns, a, b, c, d, e, and I'm selecting multiple rows:

$result = mysqli_query($conn,"SELECT a,b,c,d,e FROM posts WHERE submitter='$user'");

while ($row = mysqli_fetch_assoc($result)){
  $ratings[] = $row; 
}

Example:

The user has 3 posts, so it'll select 3 rows in the query.

I want to sum all of the rows' values for a (and the rest of course).

e.g.

row 1 a value = 4

row 2 a value = 10

row 3 a value = 1

So I need to sum all of those to get 15.


I know to use array_sum($ratings) to find the sum of the array but only if you select one column (a) which can have multiple rows, but this is multi-dimensional right due to multiple column values being selected?

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  • dongsui4658 2015-06-14 06:46
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    You can just use sum in your query:

    select sum(a)
         , sum(b)
         , sum(c)
         , sum(d)
         , sum(e)
    from posts
    where submitter = '$user'
    
    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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