很早之前就听别人说in 不走索引，但是一直没证实过，昨天在工作中用到了in所以在上班的时候突发奇想，使用mysql 的explain 关键字看下一条sql走不走索引，sql 如下所示：

explain SELECT
  * 
FROM
  lg_order 
WHERE
  logistics_number IN (
    '03245100007990077',
    '0324510000799007',
    '0323920000077348500001',
    '0329660000077348501001',
    '0322340000799007734',
    '0283920000799009498',
    '132902052979900773485',
    '03215700007998558001',
    '132284314879900s779001',
    '1329080973077348560001',
    '13292709257990077348561001',
    '1321640241777348562s001',
    '1324100421799007734ss8563001',
    '13224702197990077348561',
    '0326200000799007734s86001',
    '1327550457799007767001',
    '132836013379900768001',
  '132760071979900',
  '132249127779900')

 如上图所示，这里用到了in,但是这条sql 还是走了索引，如下图：