duplicates

问题 StackOverflow to the rescue!, I need to find the medians for five columns at once, in one query call. The median calculations below work for single columns, but when combined, multiple uses of "rownum" throws the query off. How can I update this to work for multiple columns? THANK YOU. It's to create a web tool where nonprofits can compare their financial metrics to user-defined peer groups. SELECT t1_wages.totalwages_pctoftotexp AS median_totalwages_pctoftotexp FROM ( SELECT @rownum :=

问题 Is it possible to remove duplicate characters from a string without saving each character you've seen in an array and checking to see if new characters are already in that array? That seems highly inefficient. Surely there must be a quicker method? 回答1: You can use a boolean array indexed by character : bool seen[256]; For byte-sized ASCII-like characters, the above would be appropriate. For 16-bit Unicode: bool seen[65536]; and so on. Then, for each character in the string it's a simple

问题 I am dynamically generating a query like below that creates different combinations of rules by left joining (any number of times) on itself and avoiding rules with some of the same attributes as part of the joins conditions e.g. SELECT count(*) FROM rules AS t1 LEFT JOIN rules AS t2 ON t1.id != t2.id AND ... LEFT JOIN rules AS t3 ON t1.id != t2.id AND t1.id != t3.id AND t2.id != t3.id AND ... I am currently removing duplicates by creating an array of ids from the joined rows then sorting and

问题 This question already has answers here : Removing duplicate elements from an array in Swift (41 answers) Closed 2 years ago . Say I have an array of strings: let arrayOfStrings = ["a", "b", "a", "c", "a", "d"] How would I get rid of the duplicates? 回答1: You can use the array function contains(_:) to check if an element is already part of the array, but that is fairly slow, and for large arrays it won’t perform well. (1.) Better to copy the entries into a Set and use Set operations to find and

问题 I am confused how to find out how many times a number has been repeated in a user input. I am able to input numbers and see which numbers are repeating but am unsure of how to print out each inputed number and how many times that number was used. This is what I have so far #include <stdio.h> #include <stdlib.h> int main(){ double numArray[100]; int x = 0; int y = 0; int counter = 1; int count = 0; setvbuf(stdout, NULL, _IONBF, 0); printf("Enter any number of integers between 0 and 99 followed

问题 I would like to catch 2 words sequentially duplicated in a pattern I would like to be able to catch duplicate words in this case "cancer cervical" because they are the only duplicate 2 words sequentially. pattern "cancer cervical diane mortality cervical cancer cervical diane sea" I use this Regular expression but still can't catch 2 sequentially duplicated words. /(\W|^)(.+)\s\2/ig 回答1: This should be able to do the job: /(\w+\s\w.*)\s.*\1/ if you are dealing with words including numbers.

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I need to write a function that returns the first non-repeating character in a string (case-insensitively). For example, for the string "Thanks for visiting" it should return "h" . 回答1: You could make a pass over

问题 This question already has answers here : How to find which emails are in the same lists? (3 answers) Closed 4 years ago . $sql ="SELECT u.Contact_Email FROM email1 AS u UNION ALL SELECT e.Contact_Email FROM email2 AS e"; $result = mysql_query($sql); $yes = 'yes'; $no = 'no'; echo "<table><tr><th>Email</th><th>email 1 opened</th><th>email 1 clicked</th><th>email2 opened</th><th>email2 clicked</th><th>email3 opened</th><th>email4 opened</th><th>email 4 clicked</th><th>email 5 opened</th><th

问题 I'm new to stackoverflow and I need some help. I'm trying to remove the duplicates from a multi-dimension array in PHP such as: Array ( [0] => Array ( [Plat] => hello [Data] => 01/01/2015 [Term] => PHP [Quan] => 1 ) [1] => Array ( [Plat] => hello [Data] => 01/01/2015 [Term] => PHP [Quan] => 1 ) [2] => Array ( [Plat] => hello [Data] => 03/01/2015 [Term] => PHP [Quan] => 1 ) [3] => Array ( [Plat] => hello [Data] => 03/01/2015 [Term] => PHP [Quan] => 1 ) [4] => Array ( [Plat] => hello [Data] =>

问题 How to find out duplicate records from multiple tables in MS Access based on month and the below columns ? Name, Text, Description, TestDescription select [table1].[Name], [table1].[Text], [table1].[Description], [table1].[TestDescription] From [table1] UNION ALL select [table2].[Name], [table2].[Text], [table2].[Description], [table2].[TestDescription] from [table2] WHERE Table1.month IN ("April","May") and Table2.month IN ("April","May") group by [table1].[Name], [table1].[Text], [table1].