func (qb *MySQLQueryBuilder) Having(cond string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "HAVING", cond)
	return qb
}
Having join the Having cond
package orm
import (
	"fmt"
	"strconv"
	"strings"
)
const CommaSpace = ", "
type MySQLQueryBuilder struct {
	Tokens []string
}
func (qb *MySQLQueryBuilder) Select(fields ...string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "SELECT", strings.Join(fields, CommaSpace))
	return qb
}
func (qb *MySQLQueryBuilder) ForUpdate() QueryBuilder {
	qb.Tokens = append(qb.Tokens, "FOR UPDATE")
	return qb
}
func (qb *MySQLQueryBuilder) From(tables ...string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "FROM", strings.Join(tables, CommaSpace))
	return qb
}
func (qb *MySQLQueryBuilder) InnerJoin(table string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "INNER JOIN", table)
	return qb
}
func (qb *MySQLQueryBuilder) LeftJoin(table string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "LEFT JOIN", table)
	return qb
}
func (qb *MySQLQueryBuilder) RightJoin(table string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "RIGHT JOIN", table)
	return qb
}
func (qb *MySQLQueryBuilder) On(cond string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "ON", cond)
	return qb
}
func (qb *MySQLQueryBuilder) Where(cond string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "WHERE", cond)
	return qb
}
func (qb *MySQLQueryBuilder) And(cond string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "AND", cond)
	return qb
}
func (qb *MySQLQueryBuilder) Or(cond string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "OR", cond)
	return qb
}
func (qb *MySQLQueryBuilder) In(vals ...string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "IN", "(", strings.Join(vals, CommaSpace), ")")
	return qb
}
func (qb *MySQLQueryBuilder) OrderBy(fields ...string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "ORDER BY", strings.Join(fields, CommaSpace))
	return qb
}
func (qb *MySQLQueryBuilder) Asc() QueryBuilder {
	qb.Tokens = append(qb.Tokens, "ASC")
	return qb
}
func (qb *MySQLQueryBuilder) Desc() QueryBuilder {
	qb.Tokens = append(qb.Tokens, "DESC")
	return qb
}
func (qb *MySQLQueryBuilder) Limit(limit int) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "LIMIT", strconv.Itoa(limit))
	return qb
}
func (qb *MySQLQueryBuilder) Offset(offset int) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "OFFSET", strconv.Itoa(offset))
	return qb
}
func (qb *MySQLQueryBuilder) GroupBy(fields ...string) QueryBuilder {
	qb.Tokens = append(qb.Tokens, "GROUP BY", strings.Join(fields, CommaSpace))
	return qb
}