o2o, the table is as follows:
Store shop id name
Commodity goods id name cat_id shop_id price
Category cat id name
search: query the goods that meet the criteria according to the category, list the store, and list the product data. If more than one piece of data in this store meets the criteria, list the item with the lowest price
such as looking for cat_id = 5. How to write this sql?
result field: shop_id shop_name goods_id goods_name cat_id
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I want to optimize a sentence about group by. I don t know where to start. I want to find a train of thought . SELECT adv_id, network_id, SUM(re_click) AS clk, SUM(deny_click) AS dny_clk, SUM(re_conver) AS re_ins, SUM(mat_conver) AS mat_ins, SUM(def_...
background: 1. I am a java programmer 2. Recently interviewed for a senior development position 3. The previous project mainly used less oracle,mysql, and the companies interviewed basically used mysql s 4. I am weak in the database 5. Recently, I...
like this SELECT * FROM material WHERE {key:value} limit 1 ...
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check-in table: fields include user id userid check-in time signtime timestamp type int check-in type type is divided into 0 and 1 for check-in and check-out, respectively. A user can sign twice a day, once check-in and one check-out. Check-in and ch...
Table structure ...
use mybatis to configure custom secondary cache. Using xml annotation can use < cache type= "com.test.dao.MybatisRedisCache " > to successfully use custom cache, but using @ CacheNamespace (implementation = MybatisRedisCache.class) on the dao i...
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