我試圖選擇標題的平均評分使用1表我試過的情況下,當它不工作時,當我使用CASE當它返回所有的平均值,但我需要它只是從用戶這就是選擇返回選擇如何從同一個表中選擇多個平均值php
ID USERNAME TITLE RATING RATED_BY
1 tommy Bigbear 5 oscar
2 tommy Bigbear 2 dillan
3 tommy HardLife 3 jeff
4 benben Bigbear 9 mike
我的數據庫稱爲game_ratings
$rates_select = mysqli_query($conn,"SELECT rating AS rates,
CASE WHEN title ='Bigbear' THEN AVG(rating) ELSE NULL END AS bigbear,
CASE WHEN title ='HardLife' THEN AVG(rating) ELSE NULL END AS hardlife
FROM game_ratings WHERE username='tommy'") ;
if($rate_select > 0){
$rate = mysqli_fetch_array($rate_select) ;
$rate_bigbear = $rate['bigbear'] ;
$rate_hardlife = $rate['hardlife'] ;
echo $rate_bigbear ;
}
這是回訪所有tommys收視率的平均總數不只是大熊 如果我echo $ rate_hardlife我希望它給我的平均值,如果我回聲$ rate_bigbear我想它給我平均湯米
爲什麼不簡單地使用'SELECT title,AVG(rating)AS rating from game_ratings WHERE username ='tommy'GROUP BY title'? –
如何以這種方式輸出個人標題等級,我很困惑 –