genmai.go
func (c *Condition) And(cond interface{}, args ...interface{}) *Condition {
	return c.appendQueryByCondOrExpr("And", 100, And, cond, args...)
}
func (c *Condition) And(cond interface{}, args ...interface{}) *Condition {
	return c.appendQueryByCondOrExpr("And", 100, And, cond, args...)
}
// And adds "AND" operator to the Condition and returns it for method chain.