Question

我有两个coldfusion查询，如下面的查询返回不同的列以及日期列。

<cfquery name="qry1" datasource="test">
select title, name, id, test_date from table1 , table2
</cfquery>

<cfquery name="qry2" datasource="test">
select headline, itemid, create_dt from table3 , table4
</cfquery>

我想加入这两个查询的结果，并且在最终查询中需要按日期desc排序结果（注意：2个查询中返回的日期是2个不同的列）。我知道可以选择联合所有这两个查询，我不想使用它，因为它会减慢请求。任何想法以不同的方式实现这一目标。

           <CFQUERY NAME="getDetails" DBTYPE="query"> 
                SELECT emp_id, url_shortcut, title, name, join_dt
                ,'' as item_id,'' as batch_id, '' as item_text
                FROM get_related_info_one
                 
                UNION ALL

                SELECT  to_number('') as emp_id,  '' as url_ shortcut,  '' as title, '' as name
                ,item_date as join_dt, item_id, batch_id, item_text 
                FROM get_related_info_two
            </CFQUERY>

我收到错误：查询查询语法错误。遇到“（。选择语句不正确，期待'从'，但遇到'（'相反， select语句应该有一个'FROM'结构。不知道我在这里缺少什么。

Answer 1

只要列类型相同，你就可以UNION它们。

<cfquery name="qry1" datasource="test">
select title, name, id, test_date 
from table1 , table2
UNION
select headline, '' as name, itemid, create_dt 
from table3 , table4
ORDER BY test_date
</cfquery>

Answer 2

如果您正在寻找基于CF的方法（特别是在使用内存查询查询时），Ben Nadel编写了一个QueryAppend UDF。

https://www.bennadel.com/blog/114-coldfusion-queryappend-qone-qtwo.htm

我最近做了一些调整，以便NULL日期（被ColdFusion视为“空”）不会被错误地转换。

https://gist.github.com/JamoCA/5a2adb52cbeb4e15337a7d899222072e

<!--- 7/5/2006 QueryAppend By Ben Nadel https://www.bennadel.com/blog/114-coldfusion-queryappend-qone-qtwo.htm
      1/5/2017 New "EmptyAsNull" option to prevent NULL values (dates & numbers) from being incorrectly recast
      to an invalid "empty string" by ColdFusion's Query-of-Queries and throwing "Error casting an object
      of type to an incompatible type" error. --->
<cffunction name="QueryAppend" access="public" returntype="void" output="false" hint="This takes two queries and appends the second one to the first one. This actually updates the first query and does not return anything.">
    <cfargument name="QueryOne" type="query" required="true">
    <cfargument name="QueryTwo" type="query" required="true">
    <cfargument name="EmptyAsNull" default="" required="false"> 
    <cfset var LOCAL = StructNew()>
    <cfset LOCAL.Columns = ListToArray(ARGUMENTS.QueryOne.ColumnList)>
    <cfset LOCAL.EmptyAsNull = 0>
    <cfif isValid("boolean", ARGUMENTS.EmptyAsNull) AND ARGUMENTS.EmptyAsNull>
        <cfset LOCAL.EmptyAsNull = 1>
    </cfif>
    <cfloop query="ARGUMENTS.QueryTwo">
        <cfset QueryAddRow(ARGUMENTS.QueryOne)>
        <cfloop ARRAY="#LOCAL.Columns#" index="LOCAL.ColumnName">
            <cfif StructKeyExists(ARGUMENTS.QueryTwo, LOCAL.ColumnName) AND (NOT LOCAL.EmptyAsNull OR LEN(ARGUMENTS.QueryTwo[LOCAL.ColumnName][ARGUMENTS.QueryTwo.CurrentRow]))>
                <cfset ARGUMENTS.QueryOne[LOCAL.ColumnName][ARGUMENTS.QueryOne.RecordCount] = ARGUMENTS.QueryTwo[LOCAL.ColumnName][ARGUMENTS.QueryTwo.CurrentRow]>
            </cfif>
        </cfloop>
    </cfloop>
    <cfreturn>
</cffunction>

coldfusion结合了两个查询的结果

2 个答案: