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python正则表达式抽取mysql慢查询sql本身,de-parameterize,将参数值改为?

时间:2021-07-01 10:21:17 帮助过:50人阅读

这俩其实是一条慢查询 select * from a where a>1 and b=r and c=3; select * from a where a>2 and b=x and c=5; -- 希望能处理到 select * from a where a>? and b=? and c=?

因为没有很合适的module,所以得用regrex替换。数字很容易,字符串需要考虑

  1. 最基本的,替换数字可以用r"\b\d+\b" 独立的一个或多个连续数字,这样不会替换如col1等对象中的数字
  2. 简单地,字符串可以用r"‘[^‘]*‘" 表示2个‘之间所有非‘的连续字符,这样可以适用大多数情况,除了字符串有空格的,比如‘a   bdf c‘就不行了
  3. 最严谨的方式,按‘对sql划分数组。这样所有‘‘里面的字符串都是偶数成员,其他部分奇数成员。替换偶数成员为?就可以了

代码如下import re

sql = r"select * from a where id=‘aaaaa haha wocao‘ and id1= ‘fff‘ and xx=1 and a3= 4 and a4=3434343 and a5a>99"
sql.split("")
#[select * from a where id=, aaaaa haha wocao,  and id1= , fff,  and xx=1 and a3= 4 and a4=3434343 and a5a>99]
sarr = sql.split("")
sarr
#[select * from a where id=, aaaaa haha wocao,  and id1= , fff,  and xx=1 and a3= 4 and a4=3434343 and a5a>99]
sarr[::2]
#[select * from a where id=,  and id1= ,  and xx=1 and a3= 4 and a4=3434343 and a5a>99]
sarr[1::2]
#[aaaaa haha wocao, fff]


sarr[1::2]= [? for x in sarr[1::2]]
sarr
#[select * from a where id=, ?,  and id1= , ?,  and xx=1 and a3= 4 and a4=3434343 and a5a>99]
"".join(sarr)
#"select * from a where id=‘?‘ and id1= ‘?‘ and xx=1 and a3= 4 and a4=3434343 and a5a>99"
sql
#"select * from a where id=‘aaaaa haha wocao‘ and id1= ‘fff‘ and xx=1 and a3= 4 and a4=3434343 and a5a>99"

aa = "‘".join(sarr)
re.sub(r"\b\d+\b","?",aa) 
#"select * from a where id=‘?‘ and id1= ‘?‘ and xx=? and a3= ? and a4=? and a5a>?"
 

 

python正则表达式抽取mysql慢查询sql本身,de-parameterize,将参数值改为?

标签:mysq   targe   class   pre   sql慢查询   独立   extract   slow   一个   

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