Mysql 取字段值逗号第一个数据的查询语句

selectcount(*)aslotfromOA_sample_checkwhereleft(ecnNO,LOCATE(',',ecnNO)-1)='a1'

 
select count(*) as lot from OA_sample_check where left(ecnNO, LOCATE(',',ecnNO)-1)='a1' 

Mysql 字段值 第一个数据