如我们所知,第五个参数的默认值即位数是64,因此,如果我们不对第五个参数指定任何值,则MySQL将检查不超过64位的位并产生结果。而在跳过第四个参数(即分隔符)时,MySQL在显示输出时将使用逗号(,)作为分隔符。
mysql> SELECT EXPORT_SET(8,'Y','N')\G *************************** 1. row *************************** EXPORT_SET(8,'Y','N'): N,N,N,Y,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N 1 row in set (0.00 sec)