Iterating over a Map and generating a SOQL query.

    private class WrapperMergeFieldsPreviewCampaign{
        string objectRelationShipName;
        string objectRelationshipType;
        string fieldName;
        string fieldValue;
    }

    Map<String, MergeFieldsPreviewCampaign> mergeFieldDetailsMap =  new Map<String, MergeFieldsPreviewCampaign>();
    MergeFieldsPreviewCampaign mfp = new MergeFieldsPreviewCampaign();


    mergeFieldDetailsMap.put('Account.Id',mfp.objectRelationShipName = 'Account');
    mergeFieldDetailsMap.put('Account.Id',mfp.objectRelationshipType = 'Parent');
    mergeFieldDetailsMap.put('Account.Id',mfp.fieldName = 'Id');
    mergeFieldDetailsMap.put('Account.Id',mfp.fieldValue = null);

    mergeFieldDetailsMap.put('Account.Name',mfp.objectRelationShipName = 'Account');
    mergeFieldDetailsMap.put('Account.Name',mfp.objectRelationshipType = 'Parent');
    mergeFieldDetailsMap.put('Account.Name',mfp.fieldName = 'Name');
    mergeFieldDetailsMap.put('Account.Name',mfp.fieldValue = null);

    mergeFieldDetailsMap.put('Contact.Id',mfp.objectRelationShipName = 'ReportsTo');
    mergeFieldDetailsMap.put('Contact.Id',mfp.objectRelationshipType = 'Parent');
    mergeFieldDetailsMap.put('Contact.Id',mfp.fieldName = 'Id');
    mergeFieldDetailsMap.put('Contact.Id',mfp.fieldValue = null);

    mergeFieldDetailsMap.put('Contact.LastName',mfp.objectRelationShipName = 'ReportsTo');
    mergeFieldDetailsMap.put('Contact.LastName',mfp.objectRelationshipType = 'Parent');
    mergeFieldDetailsMap.put('Contact.LastName',mfp.fieldName = 'Id');
    mergeFieldDetailsMap.put('Contact.LastName',mfp.fieldValue = null);

    mergeFieldDetailsMap.put('Contact_Child__c.Id',mfp.objectRelationShipName = 'ReportsTo');
    mergeFieldDetailsMap.put('Contact_Child__c.Id',mfp.objectRelationshipType = 'Child');
    mergeFieldDetailsMap.put('Contact_Child__c.Id',mfp.fieldName = 'Id');
    mergeFieldDetailsMap.put('Contact_Child__c.Id',mfp.fieldValue = null);

    mergeFieldDetailsMap.put('Contact_Child__c.Name',mfp.objectRelationShipName = 'Contact_Child__c');
    mergeFieldDetailsMap.put('Contact_Child__c.Name',mfp.objectRelationshipType = 'Child');
    mergeFieldDetailsMap.put('Contact_Child__c.Name',mfp.fieldName = 'Name');
    mergeFieldDetailsMap.put('Contact_Child__c.Name',mfp.fieldValue = null);

    OUTPUT OF SYSTEM.DEBUG(mergeFieldDetailsMap);

    Account.Id=MergeFieldsPreviewCampaign:[fieldName=Id, fieldValue=null, objectRelationShipName=Account, objectRelationshipType=Parent]
    Account.Name=MergeFieldsPreviewCampaign:[fieldName=Name, fieldValue=null, objectRelationShipName=Account, objectRelationshipType=Parent]
    Contact.Id=MergeFieldsPreviewCampaign:[fieldName=Id, fieldValue=null, objectRelationShipName=ReportsTo, objectRelationshipType=Parent]
    Contact.LastName=MergeFieldsPreviewCampaign:[fieldName=LastName, fieldValue=null, objectRelationShipName=ReportsTo, objectRelationshipType=Parent]
    Contact_Child__c.Id=MergeFieldsPreviewCampaign:[fieldName=Id, fieldValue=null, objectRelationShipName=Contact_Child__c, objectRelationshipType=Child]
    Contact_Child__c.Name=MergeFieldsPreviewCampaign:[fieldName=Name, fieldValue=null, objectRelationShipName=Contact_Child__c, objectRelationshipType=Child]

    There is a wrapper where I have four string fields and a Map<String, MergeFieldsPreviewCampaign> where I have allocated values for Key and Value in the above code.

    I would like to run this map (mergeFieldDetailsMap) through a loop and generate a query like below. For Contact and Parent of Contact (something like Account) , we could generate a single query and store it in a String something like below.

• Select Id,Name,Account.Name,AccountId from Contact   
• Select Id,Name from Contact_Child__c

    Please help.