func (c *Conn) sortSelectResult(r *mysql.Resultset, stmt *sqlparser.Select) error {
if stmt.OrderBy == nil {
return nil
}
sk := make([]mysql.SortKey, len(stmt.OrderBy))
for i, o := range stmt.OrderBy {
sk[i].Name = nstring(o.Expr, c.alloc)
sk[i].Direction = o.Direction
}
return r.Sort(sk)
}
func (c *Conn) limitSelectResult(r *mysql.Resultset, stmt *sqlparser.Select) error {
if stmt.Limit == nil {
return nil
}
var offset, count int64
var err error
if stmt.Limit.Offset == nil {
offset = 0
} else {
if o, ok := stmt.Limit.Offset.(sqlparser.NumVal); !ok {
return errors.Errorf("invalid select limit %s", nstring(stmt.Limit, c.alloc))
} else {
if offset, err = strconv.ParseInt(hack.String([]byte(o)), 10, 64); err != nil {
return errors.Trace(err)
}
}
}
if o, ok := stmt.Limit.Rowcount.(sqlparser.NumVal); !ok {
return errors.Errorf("invalid limit %s", nstring(stmt.Limit, c.alloc))
} else {
if count, err = strconv.ParseInt(hack.String([]byte(o)), 10, 64); err != nil {
return errors.Trace(err)
} else if count < 0 {
return errors.Errorf("invalid limit %s", nstring(stmt.Limit, c.alloc))
}
}
if offset+count > int64(len(r.Values)) {
count = int64(len(r.Values)) - offset
}
r.Values = r.Values[offset : offset+count]
r.RowDatas = r.RowDatas[offset : offset+count]
return nil
}