I like CTEs and ROW_NUMBER as the two combined allow us to see which rows are deleted (or updated), therefore just change the DELETE FROM CTE… to SELECT * FROM CTE: WITH CTE AS( SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7], RN = ROW_NUMBER()OVER(PARTITION BY col1 ORDER BY col1) FROM dbo.Table1 ) DELETE FROM … Read more
You can use groupby with function size. Then I reset index with rename column 0 to count. print df Month LSOA code Longitude Latitude Crime type 0 2015-01 E01000916 -0.106453 51.518207 Bicycle theft 1 2015-01 E01000914 -0.111497 51.518226 Burglary 2 2015-01 E01000914 -0.111497 51.518226 Burglary 3 2015-01 E01000914 -0.111497 51.518226 Other theft 4 2015-01 E01000914 … Read more
You can find your duplicates by grouping your elements by ValueA and ValueB. Do a count on them afterwards and you will find which ones are duplicates. This is how you would isolate the dupes : var duplicates = items.GroupBy(i => new {i.ValueA, i.ValueB}) .Where(g => g.Count() > 1) .Select(g => g.Key);
The approach is to have a nested query that has one line per duplicate, and an outer query returning just the count of the results of the inner query. SELECT count(*) AS duplicate_count FROM ( SELECT name FROM tbl GROUP BY name HAVING COUNT(name) > 1 ) AS t
You will get the result in O(lg n) public static void PrintIndicesForValue(int[] numbers, int target) { if (numbers == null) return; int low = 0, high = numbers.length – 1; // get the start index of target number int startIndex = -1; while (low <= high) { int mid = (high – low) / 2 … Read more
SELECT name, email, COUNT(*) FROM users GROUP BY name, email HAVING COUNT(*) > 1 Simply group on both of the columns. Note: the older ANSI standard is to have all non-aggregated columns in the GROUP BY but this has changed with the idea of “functional dependency”: In relational database theory, a functional dependency is a … Read more
yield You can use a generator for an elegant solution. At each iteration, yield twice—once with the original element, and once with the element with the added suffix. The generator will need to be exhausted; that can be done by tacking on a list call at the end. def transform(l): for i, x in enumerate(l, … Read more
I came across this and although the solution works I later came across what feels to me like a better solution. I suspect this wasn’t an option when this question was originally answered. CREATE TRIGGER `TestTable_SomeTrigger` BEFORE UPDATE ON `test_table` FOR EACH ROW BEGIN DECLARE msg VARCHAR(255); IF (SomeTestToFail = “FAIL!”) THEN set msg = … Read more