public void TestCond()
{
Cond c = Cond.Equal(Expr.Field("a"), Expr.Param("p"));
c = Cond.Like(Expr.Field("a"), Expr.Param("p"), '!');
c = Cond.Like("a", "%");
c = Cond.In(Expr.Field("a"), Qb.Select("a"));
c = Cond.IsNull(Expr.Field("a"));
c = Cond.Between(Expr.Field("a"), Expr.Param("p1"), Expr.Param("p2"));
c = Cond.Exists(Qb.Select("a"));
}