從兩個相似的列中選擇公共值

Question

我有一張表，matches，其中包含包含home_pom（匹配的主播放器）和away_pom字段的運動夾具數據。我需要調用一個查詢來查找這兩個字段中的前5個值（即，從第x季開始總共獲得比賽獎勵總數最多的5人），並且能夠輸出出現次數和玩家姓名。

我沒有真正的線索從哪裏開始使用SELECT功能。

該匹配表包含一個league_id字段，該字段對應於單獨的leagues表，該表在頁面的前面調用$ league_id。目前沒有單獨的players表 - 我認爲這可能是多餘的，因爲這幾乎是我可以考慮的唯一相關的東西。

即

match_id | homepom | awaypom | league_id 
1  | Joe A | Jane B | 2 
2  | Joe F | Jane G | 2 
3  | Jane B | Joe F | 2 

列出喬·F和簡乙作爲具有2個POM獎項，並具有一個簡G和喬甲。

$host="cust-mysql-123-05"; // Host name 
$username="unsn_637140_0003"; // Mysql username 
$password="mypw"; // Mysql password 
$db_name="nsnetballcouk_637140_db3"; // Database name 

// Connect to server and select database. 
mysql_connect("$host", "$username", "$password")or die("cannot connect"); 
mysql_select_db("$db_name")or die("cannot select DB"); 

$areatoleaguepom=$_GET['area']; 
$seasontoleaguepom=$_GET['season']; 
$divisiontoleaguepom=$_GET['division']; 
$leaguepom_query=("SELECT league_id FROM leagues WHERE area_id='$areatoleaguepom' AND  season_id='$seasontoleaguepom' AND division_id='$divisiontoleaguepom'"); 
$leaguepom_result=mysql_query($leaguepom_query); 
$leaguepom_row=mysql_fetch_array($leaguepom_result); 
$leaguepom_id=$leaguepom_row['league_id']; 

$toppom_query=(
"SELECT 
player, 
COUNT(player) as count 
FROM (SELECT homepom AS player 
FROM matches 
WHERE league_id='$leaguepom_id' 
UNION ALL 
SELECT awaypom AS player 
FROM matches 
WHERE league_id='$leaguepom_id' 
) as players 
GROUP BY player 
ORDER BY count DESC 
LIMIT 5 
"); 

$toppom_result=mysql_query($toppom_query); 
while ($toppom_row=mysql_fetch_array($toppom_result)); 

echo $toppom_row['player'] . " " . $toppom_row['count'] . "<br>"; 

有什麼想法？

Answer 1

這可能是有點過於複雜，但無論如何...

SELECT 
    player, 
    COUNT(player) as count 
FROM (
    SELECT homepom AS player 
    FROM matches 
    WHERE homepom IS NOT NULL AND homepom != '' AND league_id = xxx AND other_things 
    UNION ALL 
    SELECT awaypom AS player 
    FROM matches 
    WHERE awaypom IS NOT NULL AND awaypom != '' AND league_id = xxx AND other_things 
) as players 
GROUP BY player 
ORDER BY count DESC 
LIMIT 5 

您合併home_pom和away_pom在一列，然後做一組由數誰擁有最多的。

編輯：刪除玩家表...

Answer 2

GREATEST(home_pom, away_pom)將返回最大爲home_pom和away_pom。所以，這樣的事情：

select * from your_table 
where season = x 
order by greatest(home_pom, away_pom) 
desc limit 5 

• where條款採取季節x所有玩家記錄;
• order by .. desc按您想要的排序所有玩家記錄;
• limit 5將獲得前5名選手。