I have a trigger that works fine.  This trigger pulls weekly updates from a child object and updates fields on the Opportunity record.  There are three items on the Weekly Update object:  Status Update, Risks, & Next Steps.

trigger UpdateOpportunityStatusFromWeeklyUpdate on Weekly_Update__c (after insert, after Update) {
    for (Weekly_Update__c WU : Trigger.new) {
    
    Date dt=wu.date__c;
    String strOppId = wu.Opportunity_Name__c;
         
    List<RecordType> rtypes = [Select Name, Id From RecordType where sObjectType='Opportunity' and isActive=true];        
     //Create a map between the Record Type Name and Id for easy retrieval
     Map<String,String> opptyRecordTypes = new Map<String,String>{};
     for(RecordType rt: rtypes)
        opptyRecordTypes.put(rt.Name,rt.Id);

    
    
for (Opportunity opp : [SELECT id, name, RecordTypeId  FROM Opportunity WHERE id =: strOppId]){
   If(opp.RecordTypeId ==opptyRecordTypes.get('MMA') || opp.RecordTypeId ==opptyRecordTypes.get('MMA - Market Monitoring')) {
        String strA = dT.month() + '/' + dt.day() + '/' + dt.year()+' - ' + wu.rptOwnerName__c + ':  '+ wu.Status_Update__c ;
        String strB = dT.month() + '/' + dt.day() + '/' + dt.year()+' - ' + wu.rptOwnerName__c + ':  '+ wu.Risks__c ;
        String strC = dT.month() + '/' + dt.day() + '/' + dt.year()+' - ' + wu.rptOwnerName__c + ':  '+ wu.Next_Steps__c ;
        Opportunity O = new Opportunity(Id=wu.Opportunity_Name__c, 
                                        Opportunity_Update__c=stra,
                                        Opportunity_Next_Steps_v2__c = strc,
                                        Opportunity_Risks__c=strb,
                                        rptStatusUpateDate__c=dt);
        update O;}        
    Else {
        String strA = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ wu.Status_Update__c ;
        String strB = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ wu.Risks__c ;
        String strC = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ Next1 ;
        Opportunity O = new Opportunity(Id=wu.Opportunity_Name__c, 
                                        Opportunity_Update__c=stra,
                                        Opportunity_Next_Steps_v2__c = strc,
                                        Opportunity_Risks__c=strb,
                                        rptStatusUpateDate__c=dt);
        update O;}
}}
}

The only draw back to this code is, if one of the three fields (Status Update, Risks, & Next Steps) is Null it updates the Opportunty reocrd with the word 'Null'

So I wrote an if statement to check to see if the value was null and replace the value with 'No Report'

trigger UpdateOpportunityStatusFromWeeklyUpdate on Weekly_Update__c (after insert, after Update) {
    for (Weekly_Update__c WU : Trigger.new) {
    
    Date dt=wu.date__c;
    String strOppId = wu.Opportunity_Name__c;
         
    List<RecordType> rtypes = [Select Name, Id From RecordType where sObjectType='Opportunity' and isActive=true];        
     //Create a map between the Record Type Name and Id for easy retrieval
     Map<String,String> opptyRecordTypes = new Map<String,String>{};
     for(RecordType rt: rtypes)
        opptyRecordTypes.put(rt.Name,rt.Id);

/* ****Here is my New Code*** */
If(wu.Status_Update__c == ''){
    String Update1 = 'No Report';}
Else {
    String Update1 = wu.Status_Update__c;}
    
If(wu.Risks__c == ''){
    String Risk1 = 'No Report';}
Else {
    String Risk1 = wu.Risks__c;}
    
If(wu.Next_Steps__c == ''){
    String Next1 = 'No Report';}
Else {
    String Next1 = wu.Next_Steps__c;}        
    
for (Opportunity opp : [SELECT id, name, RecordTypeId  FROM Opportunity WHERE id =: strOppId]){
   If(opp.RecordTypeId ==opptyRecordTypes.get('MMA') || opp.RecordTypeId ==opptyRecordTypes.get('MMA - Market Monitoring')) {
        String strA = dT.month() + '/' + dt.day() + '/' + dt.year()+' - ' + wu.rptOwnerName__c + ':  '+ wu.Status_Update__c ;
        String strB = dT.month() + '/' + dt.day() + '/' + dt.year()+' - ' + wu.rptOwnerName__c + ':  '+ wu.Risks__c ;
        String strC = dT.month() + '/' + dt.day() + '/' + dt.year()+' - ' + wu.rptOwnerName__c + ':  '+ wu.Next_Steps__c ;
        Opportunity O = new Opportunity(Id=wu.Opportunity_Name__c, 
                                        Opportunity_Update__c=stra,
                                        Opportunity_Next_Steps_v2__c = strc,
                                        Opportunity_Risks__c=strb,
                                        rptStatusUpateDate__c=dt);
        update O;}        
    Else {
        String strA = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ Update1 ;
        String strB = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ Risk1 ;
        String strC = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ Next1 ;
        Opportunity O = new Opportunity(Id=wu.Opportunity_Name__c, 
                                        Opportunity_Update__c=stra,
                                        Opportunity_Next_Steps_v2__c = strc,
                                        Opportunity_Risks__c=strb,
                                        rptStatusUpateDate__c=dt);
        update O;}
}}
}

 But I am getting an error message stating: Error: Compile Error: Variable does not exist: Update1 at line 41 column 77

Which is this line:

String strA = dT.month() + '/' + dt.day() + '/' + dt.year()+ ' - '+ Update1 ;

 I am sure my error is because I put my new If statements in the wrong spot:

/* ****Here is my New Code*** */
If(wu.Status_Update__c == ''){
    String Update1 = 'No Report';}
Else {
    String Update1 = wu.Status_Update__c;}
    
If(wu.Risks__c == ''){
    String Risk1 = 'No Report';}
Else {
    String Risk1 = wu.Risks__c;}
    
If(wu.Next_Steps__c == ''){
    String Next1 = 'No Report';}
Else {
    String Next1 = wu.Next_Steps__c;} 

 Any thoughts on how to fix this.  The multiple IF statements are screwing me up!