php 一个大查询或多个小查询哪个更好？
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which is better one big query or multiple small query?
提问by Bry
which is better and efficient? one big query then just process the fetched query in the php or from php function will just create a loop function that queries small data. Please consider also that the table can be big (thousands of raw). Thanks.
哪个更好更高效？一个大查询然后只处理在 php 或从 php 函数中获取的查询将只创建一个查询小数据的循环函数。还请考虑该表可能很大（数千个原始表）。谢谢。
Comments table
评论表
id | parent | msg
---+--------+---------
1 | 0 | hello
2 | 1 | hi
3 | 2 | whats up
4 | 3 | yow
5 | 1 | hellow
6 | 2 | nice
7 | 0 | great
Expected output is this:
预期输出是这样的：
Array
(
[0] => Array
(
[id] => 1
[parent] => 0
[value] => hello
[child] => Array
(
[0] => Array
(
[id] => 2
[parent] => 1
[value] => hi
[child] => Array
(
[0] => Array
(
[id] => 3
[parent] => 2
[value] => whats up
[child] => Array
(
[0] => Array
(
[id] => 4
[parent] => 3
[value] => yow
)
)
)
[1] => Array
(
[id] => 6
[parent] => 2
[value] => nice
)
)
)
[1] => Array
(
[id] => 5
[parent] => 1
[value] => hellow
)
)
)
[1] => Array
(
[id] => 7
[parent] => 0
[value] => great
)
回答by Techie
As a rule of thumb, the less queries the better.
根据经验，查询越少越好。
This is a good question but this has been answered multiple times.
这是一个很好的问题，但已多次回答。
Is it better to return one big query or a few smaller ones?
Multiple small queries vs a single long query. Which one is more efficient?
One big query vs. many small ones?
Which one is faster single big query or few small queries?
What is faster, a big joined query with more PHP or multiple small selects with less PHP?
什么是更快，使用更多 PHP 的大连接查询或使用更少 PHP 的多个小选择？
Should I use one big SQL Select statement or several small ones?
我应该使用一个大的 SQL Select 语句还是几个小的？
https://dba.stackexchange.com/questions/76973/what-is-faster-one-big-query-or-many-small-queries
https://dba.stackexchange.com/questions/76973/what-is-faster-one-big-query-or-many-small-queries
