I think you don’t need to use the “OnComponentOk” link in this scenario.
Rather what you can do is, arrange your components as shown in the below diagram:
Once done with arranging the components, you will get two Subjobs. One will retrieve and store the global variable. The second job will retrieve and map data based on the global variable.
To perform the job go to the tSetGlobaVar and specify the timestamp pattern to your date variable. After this, go to the tMysqlInput Components and specify provide the global variables reference as shown below:
WHERE mydate >= '" + (String) globalMap.get("myDate") + "';