How to put many value in input mapping of dropdown

A few ways you can do it:

-Use Filter and advanced to specify your requirements.

-Create Sql table or Stored procedure to do the filtering as you specified. Then create smartobject from that and call it in K2.

1. Put 2 values include MG and AM in POSIT_SYS

»  First of all, you logic should handle multiple value (whether stored procedure or assembly)

    Stored procedure smartobject, you can use  string with delimiter
    Assembly smartobject, you can create serialize parameter

2. need to put start with some char (IT) in SECTCODE

»  You need to handle how you query on your logic (ex. LIKE keyword for stored procedure)

3. select null value only in RESIGN

» Stored procedure smartobject, you can define default parameter  (ex  @INPUTPARAM NVARCHAR(50)=NULL),  when null, you no need to assign value.

or if you consider empty string is NULL, you can convert it to null using NULLIF in stored procedure.