c# Regex Question "Find SQL Template Parameter in string"

Question

I am trying to parse a SQL String and look for SQL Template Parameter formatted strings. i.e. < Name, Type, Value>. I am parsing that data out to a Dictionary<String, Object>. I am not an expert in Regex, but this appears to be the best way to find the specific format, I just cannot seem to wrap my head around the Regex command I am looking for.

<.+?>

Will get me the Template Parameters I am looking for, but also catches part of a common Where statement of

WHERE (Column < value) or (column > value2)

What would be the Regex command to find all instances of "<string,string,stringornumber>" everything I tried fails to find anything, so I am sure I am just not fully grasping Regex for some reason today.

Ryan Wilson · Accepted Answer · 2022-05-11 17:07:11Z

2

This should work for you, this is a javascript example but you can change it to C#, if you need to account for other characters besides a-zA-Z0-9@_ then just add those characters into the bracket expressions:

const mysql = 'select <@test, int,  10>, <@test2, bigint, 1200000000000> from mytable where (col1 < @test) or (col1 > @test2)';
const matches = mysql.match(/<[a-zA-Z0-9@_]+?,\s*?[a-zA-Z0-9@_]+?,\s*?[a-zA-Z0-9@_]+>/g);
for(let a = 0; a < matches.length; a++){
   console.log(matches[a]);
}

EDIT

Here's a C# Example:

Regex reg = new Regex("<[a-zA-Z0-9@_]+?,\\s*?[a-zA-Z0-9@_]+?,\\s*?[a-zA-Z0-9@_]+>", RegexOptions.Multiline);        
string test = "select <@test, int,  10>, <@test2, bigint, 1200000000000> from mytable where (col1 < @test) or (col1 > @test2)";
MatchCollection matches = reg.Matches(test);
foreach(Match m in matches)
{
    Console.WriteLine(m.Value);
}

edited May 11, 2022 at 17:07

answered May 11, 2022 at 16:59

Ryan Wilson

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1 Comment

Ryan Wilson Over a year ago

So, I see someone downvoted this. Want to explain why? Or are you just going through and down voting people?

The fourth bird · Accepted Answer · 2022-05-11 20:15:59Z

1

For a broad match, you can match non whitespace characters except , < > using a negated character class:

<(?:[^\s<>,]+\s*,\s*){2}[^\s<>,]+>

The pattern matches:

< Match literally
(?: Non capture group
- [^\s<>,]+ Match 1+ non whitespace chars other than < > and ,
- \s*,\s* Match a comma between optional whitespace chars
){2} Close the non capture group and repeat 2 times
[^\s<>,]+ Match 1+ non whitespace chars other than < > and ,
> Match literally

See a regex demo.

If only the first value can start with an @ you can make the pattern stricter and start with match with @ and 1 or more word characters \w+ and only word characters for the 2nd and 3rd value:

<@\w+\s*,\s*\w+\s*,\s*\w+>

Regex demo

answered May 11, 2022 at 20:15

The fourth bird

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