genmai.go
func (c *Condition) Where(cond interface{}, args ...interface{}) *Condition {
	return c.appendQueryByCondOrExpr("Where", 0, Where, cond, args...)
}
func (c *Condition) Where(cond interface{}, args ...interface{}) *Condition {
	return c.appendQueryByCondOrExpr("Where", 0, Where, cond, args...)
}
// Where adds "WHERE" clause to the Condition and returns it for method chain.