Also

Set a = $List(list, *) 

is slower than

Set a = $List(list, 3) 

for 3-element list,  on the other hand:

Set a = $List(list) 

is faster than

Set a = $List(list, 1) 

Some comments on code.

• rename fileToImport to mysqldumpFile
• remove 2 references to other classes

That said, it does not work on my sql script on the table creation part, despite throwing no errors (data insert throws an error -  Table not found, but previous  statement which creates the table seems to run okay, but the table does not get created)

UPD: Reread your post, only INSERT, ok.

Why do you need MDX expression as a query string, through?

Hello.

Can you please publish it as a GitHub repository?

Great article, I find this feature very useful too, here's my %ZLANGC00:

 ; %ZLANGC00
 ; custom commands for ObjectScript
 ; http://localhost:57772/csp/docbook/DocBook.UI.Page.cls?KEY=GSTU_customize
  Quit    

/// Execute Query and display the results
/// Call like this:
/// zsql "SELECT TOP 10 Name FROM Sample.Person"
ZSQL(Query)
    #Dim ResultSet As %SQL.StatementResult
    Set ResultSet = ##class(%SQL.Statement).%ExecDirect(, Query)
    Do ResultSet.%Display()
    Quit

/// Move user to a namespace of his choice
/// Call like this:
/// zm "s"
ZM(Namespace)
    Do MoveToNamespace^%ZSTART(Namespace)
    Quit
    
/// Move to Samples namespace and set a as a Samples.Person object
/// Set b as %ZEN.proxyObject
/// Set c as %Object
ZO(move = 1) Public
    ZN:move "SAMPLES"
    If ##class(%Dictionary.CompiledClass).%ExistsId("Sample.Person") {
        Set p = ##class(Sample.Person).%OpenId(1)
    }
    Set a = ##class(%ZEN.proxyObject).%New()
    Set b = {}
    Quit

and related %ZSTART:

%ZSTART() {
    Quit    
}

/// This entry point is invoked on user login
/// offering user to choose a namespace
LOGIN() Public {
    Set Timeout = 3
    Write "Namespace <" _ $Namespace _ ">: "  
    Read Namespace:Timeout // Get value of a Namespace variable
    Quit:Namespace=""
    Do MoveToNamespace(Namespace)
}    

/// Does actual moving to a chosen namespace
/// This is an entry point, for cases where
/// Namespace value is already aquired
MoveToNamespace(Namespace = "") Public {
    Set Timeout = 3
    #Dim List As %ListOfDataTypes
    Set List = $$GetNamespaceList(Namespace)
    Set Count = List.Count()
    
    If Count = 1 {
        Set Choice = 1
    } ElseIf Count > 1 {
        Do DisplayList(List)

        // If there is less then 10 results, then we need only 1 digit
        // Otherwise we need 2 digits
        // It is assumed that no more then 99 results would be returned
        Read "Select number <1>: ", Choice#$Select(Count < 10:1, 1:2):Timeout

        // If the user entered nothing or not a valid number
        // we select first namespace in a list to go to
        Set:((Choice = "") || ('$IsValidNum(Choice, 0, 1, Count))) Choice = 1
    } Else {
        // No namespaces found
        Quit
    }
    
    Zn List.GetAt(Choice)
}

/// Get all availible namespaces that satisfy
/// "Name %STARTSWITH Namespace" condition
/// as %ListOfDataTypes
GetNamespaceList(Namespace = "") {
    New $Namespace
    Set $Namespace = "%SYS"

    #Dim List As %ListOfDataTypes
    #Dim ResultSet As %SQL.StatementResult
    Set List = ##class(%ListOfDataTypes).%New()

    Set UserCondition = "%UPPER(Name) %STARTSWITH %UPPER(?)"  // Or [ if you wish
    Set Condition="(" _ UserCondition _ ") AND (SectionHeader='Namespaces') AND (%UPPER(Name)!='%ALL')"
    Set SQL = "SELECT Name FROM Config.Namespaces WHERE " _ Condition

    Set ResultSet = ##class(%SQL.Statement).%ExecDirect(, SQL, Namespace)
    While ResultSet.%Next() {
        Do List.Insert(ResultSet.%Get("Name"))
    }

    Quit List
}

/// Display %ListOfDataTypes in a format:
/// 1    item
/// 2    item
/// ...
DisplayList(List) {
    #Dim List As %ListOfDataTypes
    Write !
    For i = 1:1:List.Count() {
        Write i, $C(9), List.GetAt(i), !
    }
}

Github repo.

Here's a good article on pagination I read recently. tl;dr other approaches than row numbering do exist.