Question

我收到错误;列名称“阶段”无效。我已经尝试了我能想到的每一种排列。

<cfargument name="locationFilter" default="" />
    <cfargument name="educationFilter" default="" />
    <cfargument name="workFilter" default="" />
    <cfargument name="diversityFilter" default="" />
    <cfargument name="phaseFilter" default="" />
    <cfquery name="QMentors" datasource="#request.dsn_live#">
        SELECT  
        (case 
        when datepart(year,getdate())-cast(yearstarted as integer) > 29 then '5'
        when datepart(year,getdate())-cast(yearstarted as integer) > 13 then '4'
        when datepart(year,getdate())-cast(yearstarted as integer) > 5 then '3'
        when datepart(year,getdate())-cast(yearstarted as integer) > 1 then '2'
        else '1'
        end) as phase, *
    FROM mentors 
    WHERE 0=0
    AND mentortype='mentor' 
    AND approved='true' 
    AND active='true' 
    AND mentorcat LIKE '%general%' 
        <cfif arguments.locationFilter neq ""> AND location LIKE <cfqueryparam value="%#arguments.locationFilter#%" /></cfif>
        <cfif arguments.educationFilter neq ""> AND educationhistory LIKE <cfqueryparam value="%#arguments.educationFilter#%" /></cfif>
        <cfif arguments.workFilter neq ""> AND workhistory LIKE <cfqueryparam value="%#arguments.workFilter#%" /></cfif>
        <cfif arguments.diversityFilter eq "Diversity"> AND mentorcat LIKE <cfqueryparam value="%#arguments.diversityFilter#%" /></cfif>
        <cfif arguments.phaseFilter neq ""> AND phase = <cfqueryparam value="#arguments.phaseFilter#" /></cfif>
    ORDER BY lastname
</cfquery>

我以为我最好显示整个查询。

Answer 1

试试这个

SELECT  
    (case 
    when datepart(year,getdate())-cast(yearstarted as integer) > 29 then '5'
    when datepart(year,getdate())-cast(yearstarted as integer) > 13 then '4'
    when datepart(year,getdate())-cast(yearstarted as integer) > 5 then '3'
    when datepart(year,getdate())-cast(yearstarted as integer) > 1 then '2'
    else '1'
    end) as phase, *
FROM table

编辑：

你需要重复整个案例

AND case 
    when datepart(year,getdate())-cast(yearstarted as integer) > 29 then '5'
    when datepart(year,getdate())-cast(yearstarted as integer) > 13 then '4'
    when datepart(year,getdate())-cast(yearstarted as integer) > 5 then '3'
    when datepart(year,getdate())-cast(yearstarted as integer) > 1 then '2'
    else '1'
    end) = <cfqueryparam value="#arguments.phaseFilter#" /></cfif>

或创建Select(your query) where phase = condition

Alias in where

Answer 2

你的语法错了。这段代码应该运行：

SELECT *
  FROM (SELECT case
                when datepart(year,getdate())-cast(yearstarted as integer) > 29 then '5'
                when datepart(year,getdate())-cast(yearstarted as integer) > 13 then '4'
                when datepart(year,getdate())-cast(yearstarted as integer) > 5 then '3'
                when datepart(year,getdate())-cast(yearstarted as integer) > 1 then '2'
                else '1'
               end AS phase,
       col1, col2, col3, ... -- The list of columns that you want to select
  FROM table)
WHERE plase = ...

如果要选择案例表达式，可以定义案例表达式，然后使用AS关键字给出列别名，如上所示。

如果要更新表中名为phase的列，那么您的表达式（如问题中所提供的）将是正确的。

修改

为了可维护性，在CASE子句中编写整个WHERE构造非常繁琐。相反，在内联视图（SELECT子句中的FROM语句）中使用主查询，并在phase = ...上过滤。

Answer 3

SELECT  
    case 
    when datepart(year,getdate())-cast(yearstarted as integer) > 29 then '5'
    when datepart(year,getdate())-cast(yearstarted as integer) > 13 then '4'
    when datepart(year,getdate())-cast(yearstarted as integer) > 5 then '3'
    when datepart(year,getdate())-cast(yearstarted as integer) > 1 then '2'
    else '1'
    end as phase, 
    *
FROM table

为什么SQL案例不起作用

3 个答案: