MySql 查询优化总结(一)
1、大数据分页查询,varchar 等大字段懒加载
通常代码:
SELECT aj.N_BH, aj.C_AM, aj.C_AHFROM t_aj AS ajORDER BY aj.D_LARQ DESCLIMIT 100,10
?10W 条数据,查询时间大约 ?0.73s
?
优化后:
select aj.C_AM, aj.C_AH, aj.N_BHFROM(SELECT aj.N_BH, aj.D_LARQFROM t_aj AS ajORDER BY aj.D_LARQ DESCLIMIT 100,10) T inner join t_aj aj on t.N_BH = aj.N_BH
?10W 条数据,查询时间大约 ?0.17s
?