FLOAT_AS_DOUBLE option and REAL data type join columns [CR 387270]

If a join column is a REAL data type, you must set the database option FLOAT_AS_DOUBLE to OFF when creating join indexes, or an error occurs. Issues may also result when using inexact numerics for join columns. This information was omitted from Chapter 2, “Database Options,” and Chapter 6, “SQL Statements,” Sybase IQ Reference Manual.