add pattern replace

[gywndi]

Hi~

Currently, characters are not substituted correctly in the lower case.

select * from test where a = 3*3
=> select * from test where a = ?*3

select * from test where a = ''''
=> select * from test where a = ??

First, I inserted a space character before and after the arithmetic operation code between the numbers to recognize the pattern correctly.

select * from test where a = 3*3
=> select * from test where a = 3 * 3
=> select * from test where a = ? * ?

Second, I have added code to replace from several question mark to single one

select * from test where a = ''''
=> select * from test where a = ??
=> select * from test where a = ?

Depending on the incoming parameters, the same query may be converted to two different fingerprints, so we want to fix it.

Thanks.
Chan.

[percona-csalguero]

Hi,
Thanks for sending this patch. I like the fix but it affects how handling signs between quotes work.
Check:

--- FAIL: TestFingerprintDashesInNames (0.00s)
Error Trace:    query_test.go:564
Error:          Not equal:
expected: "select benchmark(?, pow(rand(), rand())), ? from `-hj-7d6-shdj5-7jd-kf-g988h-`.`-aaahj-7d6-shdj5-7&^%$jd-kf-g988h-9+4-5*6ab-`"
actual  : "select benchmark(?, pow(rand(), rand())), ? from `-hj-7d6-shdj5 - 7jd-kf-g988h-`.`-aaahj-7d6-shdj5 - 7&^%$jd-kf-g988h-9 + 4-5 * 6ab-`"
Test:           TestFingerprintDashesInNames

[gywndi]

Ok, then it'd be better replace some pattern first and make fingerprint.
ex)

select /* my comment */ * from `mydb+1`.`tab-001` where x = 1*1 and x2 = 'mydb+1';

## step 1
select %s * from %s.%s where x = 1*1 and x2 = ?;

## step 2
select %s * from %s.%s where x = 1 * 1 and x2 = ?;

## step 3
select %s * from %s.%s where x = ? * ? and x2 = ?;

## step 4
select /* my comment */ * from `mydb+1`.`tab-001` where x = ? * ? and x2 = ?;

What do you think about this?