Parse SQL with REGEX to find Physical Update - sql

Question

I've spent a bit of time trying to bend regex to my will but its beaten me.
Here's the problem, for the following text...
--to be matched
UPDATE dbo.table
UPDATE TOP 10 PERCENT dbo.table
--do not match
UPDATE #temp
UPDATE TOP 10 PERCENT #temp
I'd like to match the first two updates statements and not match the last two update statements. So far I have the regex...
UPDATE\s?\s+[^#]
I've been trying to get the regex to ignore the TOP 10 PERCENT part as its just gets in the way. But I haven't been successful.
Thanks in advance.
I'm using .net 3.5

Answer 1

I assume you're trying to parse real SQL syntax (looks like SQL Server) so I've tried something that is more suitable for that (rather than just detecting the presence of #).
You can try regex like:
UPDATE\s+(TOP.*?PERCENT\s+)?(?!(#|TOP.*?PERCENT|\s)).*
It checks for UPDATE followed by optional TOP.*?PERCENT and then by something that is not TOP.*?PERCENT and doesn't start with #. It doesn't check just for the presence of # as this may legitimately appear in other position and not mean a temp table.

Answer 2

As I understand it, you want a regex to interact with SQL code, not actually querying a database?
You can use a negative look ahead to check if the line has #temp:
(?m)^(?!.*#temp).*UPDATE
(?!...) will fail the whole match if what's inside it matches, ^ matches the beginning of the line when combined with the m modifier. (?m) is the inline version of this modifier, as I don't know how/where you plan on using the regex.
See demo here.

Answer 3

#Robin's solution is much better but in case you needed regex with some simplier mechanisms employed I give you this:
UPDATE\s+(TOP\s+10\s+PERCENT\s+)?[a-z\.]+

Answer 4

sqlconsumer, here's a fully functioning C# .NET program. Does it do what you're looking for?
using System;
using System.Text.RegularExpressions;
class Program {
static void Main() {
string s1 = "UPDATE dbo.table";
string s2 = "UPDATE TOP 10 PERCENT dbo.table";
string s3 = "UPDATE #temp";
string s4 = "UPDATE TOP 10 PERCENT #temp";
string pattern = #"UPDATE\s+(?:TOP 10 PERCENT\s+)?dbo\.\w+";
Console.WriteLine(Regex.IsMatch(s1, pattern) );
Console.WriteLine(Regex.IsMatch(s2, pattern));
Console.WriteLine(Regex.IsMatch(s3, pattern));
Console.WriteLine(Regex.IsMatch(s4, pattern));
Console.WriteLine("\nPress Any Key to Exit.");
Console.ReadKey();
} // END Main
} // END Program
The Output:
True
True
False
False