private VectorizedRowBatch getVectorizedRowBatch1DecimalCol() {
    VectorizedRowBatch b = new VectorizedRowBatch(1);
    DecimalColumnVector v0;
    b.cols[0] = v0 = new DecimalColumnVector(18, 2);
    v0.vector[0].set(HiveDecimal.create("1.20"));
    v0.vector[1].set(HiveDecimal.create("-3.30"));
    v0.vector[2].set(HiveDecimal.create("0"));

    b.size = 3;
    return b;
  }
Spot check col >= col for decimal.
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/expressions/TestVectorFilterExpressions.java