Regex match character after lazy grouping - regex

Question

I want to match specifically the comma "," after the two groups ( AS) and (.*?).
I have a positive lookbehind that skips the AS but I cant get the grouping to skip the wildcard lazy group.
Regex:
(?<= AS)(.*?)(,)
Sample text
SELECT LEFT(CustomerCode, 5) AS SMSiteCode, SUBSTRING(CustomerCode, 6, LEN(CustomerCode) - 5) AS SMCustCode, SUBSTRING(AgreeNo, 6, LEN(AgreeNo) - 5)
AS SMAgreeNo, CAST(SeqNo AS int) AS SeqNo, SUBSTRING(TrxDate, 7, 2) + SUBSTRING(TrxDate, 4, 2) + SUBSTRING(TrxDate, 1, 2) AS TrxDate, TrxTime,
CAST(Charge AS bit) AS Charge, CASE WHEN LEN(AnalysisCode) > 5 THEN SUBSTRING(AnalysisCode, 6, LEN(AnalysisCode) - 5)
ELSE AnalysisCode END AS AnalysisCode, CAST(ISNULL(Description, N'') AS nvarchar(100)) AS Description, CAST(TaxAmt AS money) AS TaxAmt,
CAST(TotAmt AS money) AS TotAmt, CAST(Match AS bigint) AS Match, CAST(Confirmed AS bit) AS Confirmed, CAST(Balance AS money) AS Balance,
CAST(QtyBal AS money) AS QtyBal, CAST(ISNULL(Drawer, N'') AS nvarchar(50)) AS Drawer, SUBSTRING(DateBanked, 7, 2) + SUBSTRING(DateBanked, 4, 2)
+ SUBSTRING(DateBanked, 1, 2) AS DateBanked, CAST(ISNULL(BankBranch, N'') AS nvarchar(50)) AS BankBranch, CAST(Qty AS float) AS Qty, CAST(ISNULL(Narration,
N'') AS nvarchar(100)) AS Narration, SUBSTRING(DateFrom, 7, 2) + SUBSTRING(DateFrom, 4, 2) + SUBSTRING(DateFrom, 1, 2) AS DateFrom, SUBSTRING(DateTo, 7, 2)
+ SUBSTRING(DateTo, 4, 2) + SUBSTRING(DateTo, 1, 2) AS DateTo, CAST(PrintNarration AS bit) AS PrintNarration, CAST(DiscAmt AS float) AS DiscAmt,
CAST(ISNULL(CCAuthNo, N'') AS nvarchar(20)) AS CCAuthNo, CAST(ISNULL(CCTransID, N'') AS nvarchar(20)) AS CCTransID, CAST(UserLogin AS nvarchar(20))
AS UserLogin, CAST(Reconciled AS bit) AS Reconciled, SUBSTRING(DateReconciled, 7, 2) + SUBSTRING(DateReconciled, 4, 2) + SUBSTRING(DateReconciled, 1, 2)
AS DateReconciled, CAST(PrimaryKey AS bigint) AS PrimaryKey, SUBSTRING(InvDate, 7, 2) + SUBSTRING(InvDate, 4, 2) + SUBSTRING(InvDate, 1, 2) AS InvDate,
CAST(InvNo AS int) AS InvNo FROM SomeDatabase.dbo.tblTransaction WHERE IsDate(trxTime) = 1

Answer 1

You could try \K, but make sure to change Javescript in RegExr from top right of the screen to PCRE.
\K is defined as:
Sets the given position in the regex as the new "start" of the match. This means that nothing preceding the K will be captured in the overall match.
With \K, you could try something like this:
(?<= AS).*?\K(,)
Example: https://regex101.com/r/X3AdbH/1/

Answer 2

If \K is supported, you could get your matches without using a lookbehind and a capturing group by matching AS and use a negated character class to match any char except a comma.
AS [^,]+\K,
Explanation
AS Match space, AS and space
[^,]+ Match 1+ times any char except a comma
\K, Forget what was matched and match a comma
Regex demo

Answer 3

I'm guessing that your expression is just fine, you maybe want to limit the first capturing group to some specific chars, if you wish, maybe looking like:
(?<= AS)([A-Za-z\d\s]+)(,)
The expression is explained on the top right panel of regex101.com, if you wish to explore/simplify/modify it, and in this link, you can watch how it would match against some sample inputs, if you like.