有没有更好的方法来编写这个MySQL查询？

Like the question says is there a better way to write this:

就像问题所说有更好的方法来写这个:

SELECT clients_lists.*, 
       COUNT(clients_lists_relationships.clientid) 
FROM   clients_lists 
       LEFT JOIN clients_lists_relationships 
         ON clients_lists.listid = clients_lists_relationships.listid 
WHERE  clients_lists.parentid = 1 
GROUP  BY clients_lists.listid;

1 个解决方案

#1

Not really. The query looks fine to me. You can try to use aliases for better readability:

不是真的。查询看起来很好。您可以尝试使用别名以获得更好的可读性:

SELECT c.*, 
       COUNT(r.clientid) 
FROM   clients_lists c
       LEFT JOIN clients_lists_relationships r
         ON c.listid = r.listid 
WHERE  c.parentid = 1 
GROUP  BY c.listid;

But it won't really make a technical difference (not that I know).

但它不会真正产生技术差异(不是我所知道的)。

Also make sure that both clients_lists.listid and clients_lists_relationships.listid are of the same datatype and length and are indexed. This will definitely help your query's performance.

还要确保clients_lists.listid和clients_lists_relationships.listid具有相同的数据类型和长度并且已编制索引。这肯定有助于查询的性能。

1 个解决方案

#1

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