用SUM优化选择…案例

Question

有什么方法可以优化此查询：

select 
orders_id,
orders_products_id,
sum(CASE products_options_id WHEN 1 THEN products_options_values_id ELSE 0 END) as color,
sum(CASE products_options_id WHEN 2 THEN products_options_values_id ELSE 0 END) as talle

from 
orders_products_attributes 

group by 
orders_products_id

这是EXPLAIN输出：

id  select_type   table                       type   possible_keys   key   key_len   ref     rows   Extra
1   SIMPLE        orders_products_attributes  ALL    NULL            NULL  NULL      NULL  69006  Using temporary; Using filesort

谢谢！

卢西亚诺

Answer 1

我建议使用列（orders_product_id，products_options_id，orders_id）为此查询创建覆盖索引。

CREATE INDEX ix_opa_opid_poid_oid
    ON orders_products_attributes (orders_product_id, products_options_id, orders_id)