func (l WhenList) When(c qb.Condition, v interface{}) WhenList {
	var (
		f  qb.Field
		ok bool
	)
	if f, ok = v.(qb.Field); !ok {
		f = qb.Value(v)
	}
	return append(l, when{C: c, F: f})
}
When adds a statement to the list
package qf
import (
	"strings"
	"git.ultraware.nl/NiseVoid/qb"
)
type when struct {
	C qb.Condition
	F qb.Field
}
type WhenList []when
func Case() WhenList {
	return WhenList{}
}