表格:CREATETABLE`T1`(`UserId`int(10)unsignedNOTNULL,`FriendUserId`int(10)unsignedNOTNULL,`IsDisplayed`tinyint(1)unsignedNOTNULL,`Created`datetimeNOTNULL,KEY`FriendUserId`(`FriendUserId`,`IsDisplayed`,`UserId`,`Created`))ENGINE=MyISAMDEFAULTCHARSET=utf8;查询:SELECT`UserId`,`FriendUserId`,UNIX_TIMESTA

表格:CREATETABLE`T1`(`UserId`int(10)unsignedNOTNULL,`FriendUserId`int(10)unsignedNOTNULL,`IsDisplayed`tinyint(1)unsignedNOTNULL,`Created`datetimeNOTNULL,KEY`FriendUserId`(`FriendUserId`,`IsDisplayed`,`UserId`,`Created`))ENGINE=MyISAMDEFAULTCHARSET=utf8;查询:SELECT`UserId`,`FriendUserId`,UNIX_TIMESTA