我的代码出了什么问题？ （如果上一列不为null，则更新下一列）

Question

我最近开始使用PHP和MySQL，我编写了一个代码，用于将变量插入到MySQL列中，如果此列已经填充（Not NULL），那么它将继续并尝试更新下一列。这是我的代码：

$result=mysql_query("
UPDATE user_info SET   
 Amount20 = ( case when ( Amount19 is not null and Amount20 is null ) then ‘$amount’ WHERE Username ='$user' else Amount20 end )

,   Amount19 = ( case when ( Amount18 is not null and Amount19 is null ) then ‘$amount’ WHERE Username ='$user' else Amount19 end )

,   Amount18 = ( case when ( Amount17 is not null and Amount 18 is null ) then ‘$amount’ WHERE Username ='$user' else Amount18 end )

,   Amount17 = ( case when ( Amount16 is not null and Amount17 is null ) then ‘$amount’ WHERE Username ='$user' else Amount17 end )

,   Amount16 = ( case when ( Amount15 is not null and Amount16 is null ) then ‘$amount’ WHERE Username ='$user' else Amount16 end )

,   Amount15 = ( case when ( Amount14 is not null and Amount15 is null ) then ‘$amount’ WHERE Username ='$user' else Amount15 end )

,   Amount14 = ( case when ( Amount13 is not null and Amount14 is null ) then ‘$amount’ WHERE Username ='$user' else Amount14 end )

,   Amount13 = ( case when ( Amount12 is not null and Amount13 is null ) then ‘$amount’ WHERE Username ='$user' else Amount13 end )

,   Amount12 = ( case when ( Amount11 is not null and Amount12 is null ) then ‘$amount’ WHERE Username ='$user' else Amount12 end )

,   Amount11 = ( case when ( Amount10 is not null and Amount11 is null ) then ‘$amount’ WHERE Username ='$user'else Amount11 end )

,   Amount10 = ( case when ( Amount9 is not null and Amount10 is null ) then ‘$amount’ WHERE Username ='$user' else Amount10 end )

,   Amount9 = ( case when ( Amount8 is not null and Amount9 is null ) then ‘$amount’ WHERE Username ='$user' else Amount9 end )

,   Amount8 = ( case when ( Amount7 is not null and Amount8 is null ) then ‘$amount’ WHERE Username ='$user' else Amount8 end )

,   Amount7 = ( case when ( Amount6 is not null and Amount7 is null ) then ‘$amount’ WHERE Username ='$user' else Amount7 end )

,   Amount6 = ( case when ( Amount5 is not null and Amount6 is null ) then ‘$amount’ WHERE Username ='$user' else Amount6 end )

,   Amount5 = ( case when ( Amount4 is not null and Amount5 is null ) then ‘$amount’ WHERE Username ='$user' else Amount5 end )   

,   Amount4 = ( case when ( Amount3 is not null and Amount4 is null ) then ‘$amount’ WHERE Username ='$user' else Amount4 end )

,   Amount3 = ( case when ( Amount2 is not null and Amount3 is null ) then ‘$amount’ WHERE Username ='$user' else Amount3 end )  

, Amount2 = ( case when ( Amount1 is not null and Amount2 is null ) then ‘$amount’ WHERE Username ='$user' else Amount2 end )  

, Amount1 = ( case when ( Amount1 is null ) then '$amount' else Amount1 WHERE Username ='$user' end )  
");

我不知道出了什么问题，任何帮助都会很棒！ 注意：我有理由有20个不同的列，请不要将我引用到“规范化”。

Answer 1

我按如下方式修改了您的查询：

$result=mysql_query("
UPDATE user_info SET   
Amount20 = ( case when ( Amount19 is not null and Amount20 is null ) then ‘$amount’    else Amount20 end )
,Amount19 = ( case when ( Amount18 is not null and Amount19 is null ) then ‘$amount’ else Amount19 end )
,Amount18 = ( case when ( Amount17 is not null and Amount 18 is null ) then ‘$amount’ else Amount18 end )
,Amount17 = ( case when ( Amount16 is not null and Amount17 is null ) then ‘$amount’ else Amount17 end )
,Amount16 = ( case when ( Amount15 is not null and Amount16 is null ) then ‘$amount’ else Amount16 end )
,Amount15 = ( case when ( Amount14 is not null and Amount15 is null ) then ‘$amount’ else Amount15 end )
,Amount14 = ( case when ( Amount13 is not null and Amount14 is null ) then ‘$amount’ else Amount14 end )
,Amount13 = ( case when ( Amount12 is not null and Amount13 is null ) then ‘$amount’ else Amount13 end )
,Amount12 = ( case when ( Amount11 is not null and Amount12 is null ) then ‘$amount’ else Amount12 end )
,Amount11 = ( case when ( Amount10 is not null and Amount11 is null ) then ‘$amount’ else Amount11 end )
,Amount10 = ( case when ( Amount9 is not null and Amount10 is null ) then ‘$amount’ else Amount10 end )
,Amount9 = ( case when ( Amount8 is not null and Amount9 is null ) then ‘$amount’ else Amount9 end )
,Amount8 = ( case when ( Amount7 is not null and Amount8 is null ) then ‘$amount’ else Amount8 end )
,Amount7 = ( case when ( Amount6 is not null and Amount7 is null ) then ‘$amount’ else Amount7 end )
,Amount6 = ( case when ( Amount5 is not null and Amount6 is null ) then ‘$amount’ else Amount6 end )
,Amount5 = ( case when ( Amount4 is not null and Amount5 is null ) then ‘$amount’ else Amount5 end )   
,Amount4 = ( case when ( Amount3 is not null and Amount4 is null ) then ‘$amount’ else Amount4 end )
,Amount3 = ( case when ( Amount2 is not null and Amount3 is null ) then ‘$amount’ else Amount3 end )  
,Amount2 = ( case when ( Amount1 is not null and Amount2 is null ) then ‘$amount’ else Amount2 end )  
,Amount1 = ( case when ( Amount1 is null ) then '$amount' else Amount1 end )
 WHERE Username ='$user'");