将两个选择的SQL查询合并为一个

Question

"id"    "type"  "parent"    "country"   "votes" "perCent"
"1"     "1"     "0"         "US"        "0"     "0"
"2"     "3"     "1"         "US"        "105"   "0"// Total
"3"     "10"    "2"         "US"        "15"    "0"
"4"     "10"    "2"         "US"        "50"    "0"
"5"     "10"    "2"         "US"        "25"    "0"
"6"     "10"    "2"         "US"        "5"     "0"
"7"     "10"    "2"         "US"        "10"    "0"

"8"     "1"     "0"         "US"        "0"     "0"
"9"     "3"     "8"         "US"        "80"    "0"// Total
"10"    "10"    "9"         "US"        "10"    "0"
"11"    "10"    "9"         "US"        "5"     "0"
"12"    "10"    "9"         "US"        "15"    "0"
"13"    "10"    "9"         "US"        "20"    "0"
"14"    "10"    "9"         "US"        "30"    "0"

In the above table likes , I have the total votes stored in a type = 3 row.

I'm trying to update the perCent column with the percentage of votes each has got where type = 10.

I do this right now in php like below. Can the first two statements be combined into one? I lost trying with joins and inner joins etc.

The way I currently do things in php is as follows:

select id, votes as totalVotes from likes where type = 3 and country = 'us';

select votes from likes where parent = id and type = 10;

update votes set votes = (100*10/totalVotes) where type = 10 and parent = id;

Results I trying to achieve:

"id"    "type"  "parent"    "country"   "votes" "perCent"
    "1"     "1"     "0"         "US"        "0"     "0"
    "2"     "3"     "1"         "US"        "105"   "0"// Total
    "3"     "10"    "2"         "US"        "15"    "14.28" (100*15/105)
    "4"     "10"    "2"         "US"        "50"    "47.61"
    "5"     "10"    "2"         "US"        "25"    "23.80"
    "6"     "10"    "2"         "US"        "5"     "4.76"
    "7"     "10"    "2"         "US"        "10"    "9.53"

    "8"     "1"     "0"         "US"        "0"     "0"
    "9"     "3"     "8"         "US"        "80"    "0"// Total
    "10"    "10"    "9"         "US"        "10"    "12.5"
    "11"    "10"    "9"         "US"        "5"     "6.25"
    "12"    "10"    "9"         "US"        "15"    "18.75"
    "13"    "10"    "9"         "US"        "20"    "25.00"
    "14"    "10"    "9"         "US"        "30"    "37.50"

Answer 1

Check SQLFiddle .

UPDATE `votestable` v
SET v.`percent` = (SELECT
                     ROUND( ( ( v.votes * 100) / v1.votes ), 2 )
                   FROM (SELECT
                           votes,
                           id
                         FROM Votestable) AS v1
                   WHERE v1.id = v.parent)

Answer 2

This should do what you're asking, updating all products' percentages to reflect their part of the total votes under their heading;

UPDATE likes p
JOIN likes h
  ON p.parent = h.id
 AND p.type=10 AND h.type=3
 AND h.country = 'US'
SET p.percent=100*p.votes/h.votes;

An SQLfiddle to test with .

Answer 3

If I'm not mistaken, this looks like a left join to me.

SELECT lp.id, lp.votes + COALESCE(SUM(lc.votes), 0) as totalVotes FROM likes lp
    LEFT JOIN likes lc ON lc.parent = lp.id AND lc.type = 10
    WHERE lp.type = 3 AND lp.country = 'us'