;WITH OrderedALog AS
(
  SELECT 
    Aid, ACode, ATimestamp,
    ROW_NUMBER() OVER (PARTITION BY Aid ORDER BY ACode DESC, ATimestamp) RowNum
  FROM 
    dbo.ALog al 
  WHERE 
    AId > 0 AND ACode IN ('Generatedocument', 'RunQuote')
)
INSERT INTO 
  dbo.A
SELECT
  Aid, ACode, ATimestamp
FROM
  OrderedALog
WHERE
  RowNum = 1

INSERT INTO tableA (Aid, ACode, ATimestamp)
SELECT 
	Aid
	,ACode
	,MIN(ATimestamp) ATimestamp
FROM dbo.ALog al 
WHERE AId > 0 
	AND ACode IN ('RunQuote', 'Generatedocument')
GROUP BY ACode, Aid
ORDER BY ACode, Aid

12345 'runquote        '   1
12345 'Generatedocument'   2
23456 'runquote        '   1
23456 'Generatedocument'   2
34567 'Generatedocument'   1