How to take two sql queries and combine them into a single query

I am making progress on a custom script for my program:

// You might want to use a date range and specify the first Sunday and use that variable.
// Or, you may want to have a user request variable where they key in the starting Sunday #YYYY MM DD#

// Let us work out the current week number
$iStartWeekNumber = $Today#CUSTOMDATE[%W] + 1
TEXT "Current week number (1 to 52): $iStartWeekNumber"
EOL

// Let us work out the current year
$iThisYear = $Today#CUSTOMDATE[%Y]
TEXT "Current year: $iThisYear"
EOL

// Now we can do a manual for loop from iStartWeekNumber to the end of the year
TEXT "TODO: Work out how to show the date nicely formatted"
EOL
$datWeek = $Today
LOOP AS $iWeekNumber FROM $iStartWeekNumber TO 52
    $datWeek = $datWeek + 7
    TEXT "Week: $iWeekNumber"
    EOL
    TEXT "Date: {$datWeek#SHORTDATE}"
    EOL

    // Iterate all available speakers
    LOOP FROM "Congregation Speakers" NODATERANGE WHERE "Congregation" IS "$LocalCong" AND "notavail" IS "0"  SORTBY "Speaker"

        // Requirement 1
        // 1. He is not in program for a talk in our home or another congregation for that same WEEKEND (either saturday or sunday)

        // Store the current speaker into a variable
        VARIABLE_FIELD "Speaker" "$strCurrentSpeaker"

        LOOP SQL "SELECT * FROM [Home Talks] WHERE ((DatePart('ww',[Last Given],2)=$iWeekNumber)) AND ((DatePart('yyyy',[Last Given])=$iThisYear)) AND [Speaker] = '$strCurrentSpeaker' AND [Congregation]='$LocalCong'" ROW_COUNT "$iNumHomeTalks"
        END_LOOP

        LOOP SQL "SELECT * FROM [Away Talks] WHERE ((DatePart('ww',[Talk Date],2)=$iWeekNumber)) AND ((DatePart('yyyy',[Talk Date])=$iThisYear)) AND [Brother] = '$strCurrentSpeaker'" ROW_COUNT "$iNumAwayTalks"
        END_LOOP

        IF "$iNumHomeTalks" IS "0" AND "$iNumAwayTalks" IS "0"
            // Requirement 2
            // 2. He should not give a talk more than once in a MONTH (so he is unavailable if he will be giving a talk during the month)
            $iMonth = date_part($datWeek,"M")
            LOOP SQL "SELECT * FROM [Home Talks] WHERE ((DatePart('m',[Last Given])=$iMonth)) AND ((DatePart('yyyy',[Last Given])=$iThisYear)) AND [Speaker] = '$strCurrentSpeaker' AND [Congregation]='$LocalCong'" ROW_COUNT "$iNumHomeTalksForMonth"
            END_LOOP
            LOOP SQL "SELECT * FROM [Away Talks] WHERE ((DatePart('m',[Talk Date])=$iMonth)) AND ((DatePart('yyyy',[Talk Date])=$iThisYear)) AND [Brother] = '$strCurrentSpeaker'" ROW_COUNT "$iNumAwayTalksForMonth"
            END_LOOP
            $iTotalTalksForMonth = $iNumHomeTalksForMonth + $iNumAwayTalksForMonth
            IF "$iTotalTalksForMonth" IS "0"
                // Requirement 3
                // 3. That same weekend either one or more than x speakers are not out for a talk or unavailable

                // TO DO
                TEXT "$strCurrentSpeaker"
                EOL
            END_IF
        END_IF
    END_LOOP

    BLANK *1
END_LOOP

I want to specifically bring your attention to two sets of SQL queries:

Set 1:

LOOP SQL "SELECT * FROM [Home Talks] WHERE ((DatePart('ww',[Last Given],2)=$iWeekNumber)) AND ((DatePart('yyyy',[Last Given])=$iThisYear)) AND [Speaker] = '$strCurrentSpeaker' AND [Congregation]='$LocalCong'" ROW_COUNT "$iNumHomeTalks"
END_LOOP
LOOP SQL "SELECT * FROM [Away Talks] WHERE ((DatePart('ww',[Talk Date],2)=$iWeekNumber)) AND ((DatePart('yyyy',[Talk Date])=$iThisYear)) AND [Brother] = '$strCurrentSpeaker'" ROW_COUNT "$iNumAwayTalks"
END_LOOP

And set 2:

LOOP SQL "SELECT * FROM [Home Talks] WHERE ((DatePart('m',[Last Given])=$iMonth)) AND ((DatePart('yyyy',[Last Given])=$iThisYear)) AND [Speaker] = '$strCurrentSpeaker' AND [Congregation]='$LocalCong'" ROW_COUNT "$iNumHomeTalksForMonth"
END_LOOP
LOOP SQL "SELECT * FROM [Away Talks] WHERE ((DatePart('m',[Talk Date])=$iMonth)) AND ((DatePart('yyyy',[Talk Date])=$iThisYear)) AND [Brother] = '$strCurrentSpeaker'" ROW_COUNT "$iNumAwayTalksForMonth"
END_LOOP

The above is my own scripting language. But under the hood it takes the raw SQL queries and runs it on a Microsoft Access Database using Jet.

They work fine. But I am wondering if the two sets of queries can be combined into one? As you can see, all I am trying to establish is the number of records found. So if I could combine the queries of the [Home Talks] and [Away Talks] I would end up with only 2 queries to execute instead of four.

It looks to me that I need to use UNION but one of the fields is different in each table:

Last Given
Talk Date

So I can't just stitch the keyword UNION in between the two queries.

Solution

You can use UNION by aliasing the field names:

SELECT [Last Given] AS MyFieldName FROM [Home Talks]
UNION
SELECT [Talk Date] AS MyFieldName FROM [Away Talks]

You just have to list individual fields instead of * and make sure any output fields match type (or convert to string as part of your query) and name (alias).

Edit: This is an additional option if the two fields are completely unrelated (as opposed to the same or similar information with different field names):

SELECT [Last Given], NULL AS [Talk Date] FROM [Home Talks]
UNION
SELECT NULL AS [Last Given], [Talk Date] FROM [Away Talks]