Question

I have a table as given below

RMG Date        Value
YA  11/02/2001  94
YB  11/02/2011  63
YC  11/02/2011  35
YA  12/02/2011  32
YB  12/02/2011  45
YC  12/02/2011  51
YA  13/02/2011  32
YB  13/02/2011  45
YC  13/02/2011  51

Based on requirement I want to extract common date and show it like

  RMG         11/02/2011      12/02/2011    13/02/2011
  YA           94                 32             32
  YB           63                 45             45
  YC           35                 51             51

How can I achieve this using table in Java or by SQL. I have no background in database. I am confused what is the best approach to fix this.

Answer 1

How can I find the matching dates to put it into in(…)?

The pivot_in_clause of select appears to accept a subquery, such as this:

select distinct(Date) from DbTable

Addendum: If XML is unacceptable with a subquery, a separate query may be used to determine the distinct values required. As a concrete example, the following method will return a List of unique dates from DBTable. The list is suitable for constructing the IN clause of the pivot.

private static List<Date> getDates(Connection conn) throws SQLException {
    List<Date> list = new ArrayList<Date>();
    StringBuilder sb = new StringBuilder();
    Statement st = conn.createStatement();
    st.execute("select distinct(Date) from DbTable");
    ResultSet rset = st.getResultSet();
    while (rset.next()) {
        list.add(rset.getDate(1));
    }
    return list;
}

Addendum: Additional guidance may be found in the JDBC™ Database Access tutorial and the Oracle® Database JDBC Developer’s Guide.