SQL优化

SQL查询优化实践

最新推荐文章于 2024-11-26 11:59:09 发布

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SQl 优化的方式：

explain select vend_id,prod_id,prod_price
 from products
 where prod_price<=5
 Union 
select vend_id,prod_id,prod_price
from products
where vend_id in(1001,1002);

1   PRIMARY   products       ALL                   14   33.33   Using where
2   UNION   products       ALL   fk_products_vendors               14   35.71   Using where
   UNION RESULT   <union1,2>       ALL                           Using temporary