MERGE 
    [ DRY ] 
    [ ReferenceType ] 
    ExistingReference 
    [ AT [ TIMESTAMP | COMMIT ] TimestampOrCommit ] 
    [ INTO ExistingReference ] 
    [ BEHAVIOR MergeBehaviorKind ] 
    [ BEHAVIORS ContentKey = MergeBehaviorKind { AND ContentKey = MergeBehaviorKind } ] 
    [ IN CatalogName ]