Case statement for date format conversion in oracle : I have a "Entrydate" field that comes from Source in below date format 

 1) YYYY-MM-DD HH.MM.SS

 2) YYYY-MM-DD 

It is loaded to a table as "YYYMM" format . I am looking for a case statement that handles both the conditions. 

I am using the below SQL

    SELECT CASE WHEN
    to_char(ENTRYDATE, 'YYYY-MM-DD HH.MM.SS') THEN to_char(ENTRYDATE, 'YYYYMM')
    to_char(ENTRYDATE, 'YYYY-MM-DD') THEN to_char(ENTRYDATE, 'YYYYMM')
    FROM TABLE;

 
I will need to get the date in 'yyyymm' format to validate the output table. Getting "invalid relational operator" errror.  Could someone help me with this. Thanks!