Get table ID after insert with ColdFusion and MySQL

Here is a quick solution for MSSQL. It uses the SCOPE_IDENTITY() function that returns the ID of the last row inserted in the previous insert statement.

http://msdn.microsoft.com/en-us/library/ms190315.aspx

<cfquery>
    DECLARE @iNewGeneratedID INT

    INSERT INTO transactions
        (
            transactionDate,
            transactionAmount
        )
    VALUES
       (
            <cfqueryparam value="#transactionDate#" type="cf_sql_date">,
            <cfqueryparam value="#transactionAmount#" type="cf_sql_integer">
       )

    SET @iNewGeneratedID = SCOPE_IDENTITY()

    INSERT INTO transactionItems
        (
            transactionID,
            itemID,
            itemAmount
        )
    VALUES
        (
            @iNewGeneratedID,
           <cfqueryparam value="#itemID#" type="cf_sql_integer">,
           <cfqueryparam value="#itemAmount#" type="cf_sql_integer">
        )

    SELECT @iNewGeneratedID AS iNewGeneratedID
</cfquery>

Part 1: I would personally not batch multiple statements within a single query to reduce the risk of SQL injection. This is a setting within your datasource on the ColdFusion administrator. Executing a stored procedure, which might be what you are doing(?), is another story, but, you should rephrase your question to "Get primary key after insert with mySQL Stored Procedure" if that is your intention.

Part 2: ColdFusion, like many things, makes getting the primary key for a newly inserted record very easy--even if you are using auto-increment keys, GUIDs or something like Oracle's ROWNUM. This will work on any almost every database supported by Adobe ColdFusion including MSSQL or MySQL. The only exception is the version of the databse--for example, MySQL 3 will not support this; however, MySQL 4+ will.

<cfquery result="result">
  INSERT INTO myTable (
      title
  ) VALUES (
    <cfqueryparam value="Nice feature!" cfsqltype="cf_sql_varchar">
  )
</cfquery>

<--- get the primary key of the inserted record --->
<cfset NewPrimaryKey = result.generatedkey>

As of CF9+, you can access the new ID (for any database) using the generic key name:

result.GENERATEDKEY    // All databases

For CF8, different databases will have different keys within the results value. Here is a simple table to help I copied from the cfquery documentation.

result.identitycol    // MSSQL
result.rowid          // Oracle
result.sys_identity   // Sybase
result.serial_col     // Informix
result.generated_key  // MySQL

If you have any questions you can see a pretty dump as follows:

<cfdump var="#result#" />