In the online tutorial of comparison analysis, when you make the formula, if some genes are repeated in more than 2 groups, how could we to make that table?

Meanwhile, when I convert the gene symbol to ENTREZID, always have this warning msg. Actually, all of the genes have matched and converted, nothing missed.

select()' returned 1:1 mapping between keys and columns
Warning message:
In bitr(rownames(VAC_timecourse_DEG_Day28), fromType = "SYMBOL",  :
  0.28% of input gene IDs are fail to map...

for example, geneA in group A, B, C, just use something like:

gene            group

geneA            A

geneA            B

geneA            C

geneB            A

Then you can use compareCluster(gene ~ group, ...)

The warning message is OK