Question

我目前将行添加到一起的方法是这样的：

$totalxp = $row['Attackxp'] + $row['Defencexp'] + $row['Strengthxp'] + $row['Hitpointsxp'] + $row['Rangedxp'] + $row['Prayerxp'] + $row['Magicxp'] + $row['Cookingxp'] + $row['Woodcuttingxp'] + $row['Fletchingxp'] + $row['Fishingxp'] + $row['Firemakingxp'] + $row['Craftingxp'] + $row['Smithingxp'] + $row['Miningxp'] + $row['Herblorexp'] + $row['Agilityxp'] + $row['Thievingxp'] + $row['Slayerxp'] + $row['Farmingxp'] + $row['Runecraftxp'] + $row['Constructionxp'];

但后来我看到了SUM（），我尝试了这个：

SELECT SUM(xp) FROM skills WHERE playerName='Undercover'

它有效，但我需要xp的所有值，所以我尝试添加%xp，但它无法正常工作。

我如何使用Sum（）函数添加所有行而不是使PHP变形？

Answer 1

聚合函数（IE：SUM，MIN，MAX，COUNT等）不能跨列工作 - 它们根据分组（GROUP BY）和过滤（特定列）处理特定列的值（ JOIN和/或WHERE条款。

要在列之间添加值，您需要像对常规数学方程式一样添加它们：

SELECT Attackxp + Defencexp + Strengthxp + Hitpointsxp + Rangedxp + Prayerxp + Magicxp + Cookingxp+ Woodcuttingxp + Fletchingxp + Fishingxp + Firemakingxp + Craftingxp + Smithingxp + Miningxp + Herblorexp + Agilityxp + Thievingxp + Slayerxp + Farmingxp + Runecraftxp + Constructionxp AS total_xp
  FROM skills 
 WHERE playerName = 'Undercover'

如果你有一个与玩家名相关联的记录，那么你可以使用聚合函数：

SELECT SUM(Attackxp + Defencexp + Strengthxp + Hitpointsxp + Rangedxp + Prayerxp + Magicxp + Cookingxp+ Woodcuttingxp + Fletchingxp + Fishingxp + Firemakingxp + Craftingxp + Smithingxp + Miningxp + Herblorexp + Agilityxp + Thievingxp + Slayerxp + Farmingxp + Runecraftxp + Constructionxp) AS total_xp
  FROM skills 
 WHERE playerName = 'Undercover'

Answer 2

这取决于表数据，如果每个玩家是一个实体（行），那么就可以添加列：

SELECT Attackxp  + Defencexp + Strengthxp + Hitpointsxp +Rangedxp + Prayerxp + Magicxp + Cookingxp + Woodcuttingxp + Fletchingxp + Fishingxp + Firemakingxp + Craftingxp + Smithingxp + Miningxp + Herblorexp + Agilityxp + Thievingxp + Slayerxp + Farmingxp + Runecraftxp + Constructionxp 
As totalSkills FROM skills WHERE playerName = 'Undercover'

但是每个玩家有更多的行然后您还需要对行进行求和

SELECT SUM(Attackxp  + Defencexp + Strengthxp + Hitpointsxp +Rangedxp + Prayerxp + Magicxp + Cookingxp + Woodcuttingxp + Fletchingxp + Fishingxp + Firemakingxp + Craftingxp + Smithingxp + Miningxp + Herblorexp + Agilityxp + Thievingxp + Slayerxp + Farmingxp + Runecraftxp + Constructionxp) 
As totalSkills FROM skills WHERE playerName = 'Undercover'

Answer 3

SELECT SUM(`Attackxp`) + SUM(`Defencexp`) + ... AS `total_sum`
  FROM skills
 WHERE playerName='Undercover'

如何使用SUM（）来求和结果数组？

3 个答案: