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How to find all duplicate from a List? [duplicate]
...d then filter out any of the enumerables that have a Count of <=1, then select their keys to get back down to a single enumerable:
var duplicateKeys = list.GroupBy(x => x)
.Where(group => group.Count() > 1)
.Select(group => group.Key);
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How to change options of with jQuery?
Suppose a list of options is available, how do you update the <select> with new <option> s?
9 Answers
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oracle top 替代方案 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
oracle top 替代方案由于Oracle不支持select top 语句，所以在Oracle中经常是用order by 跟 rownum的组合来实现select top n的查询。select * from (...由于Oracle不支持select top 语句，所以在Oracle中经常是用order by 跟 rownum 的组合来实现select top n的查...
PostgreSQL: How to pass parameters from command line?
...3="'2010-11-12'"
and then refer to the variables in sql as :v1, :v2 etc
select * from table_1 where id = :v1;
Please pay attention on how we pass string/date value using two quotes " '...' "
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How can I select the first day of a month in SQL?
I just need to select the first day of the month of a given datetime variable.
30 Answers
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How to get size of mysql database?
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Run this query and you'll probably get what you're looking for:
SELECT table_schema "DB Name",
ROUND(SUM(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB"
FROM information_schema.tables
GROUP BY table_schema;
This query comes from the mysql forums, where there are...
Visual Studio - Shortcut to Navigate to Solution Explorer
Is there a keyboard shortcut in Visual Studio (aside from CTRL + TAB and selection) that would take me from inside a document directly into the solution explorer? I don't want to customize any shortcuts or change any default behavior.
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INSERT IF NOT EXISTS ELSE UPDATE?
...ike:
insert or replace into Book (ID, Name, TypeID, Level, Seen) values
((select ID from Book where Name = "SearchName"), "SearchName", ...);
Note that any field not in the insert list will be set to NULL if the row already exists in the table. This is why there's a subselect for the ID column: I...
How do I list all the columns in a table?
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For Oracle (PL/SQL)
SELECT column_name
FROM user_tab_cols
WHERE table_name = 'myTableName'
For MySQL
SHOW COLUMNS FROM table_name
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What is the best way to paginate results in SQL Server
... sake of this example, let's assume that the query you're dealing with is
SELECT * FROM Orders WHERE OrderDate >= '1980-01-01' ORDER BY OrderDate
In this case, you would determine the total number of results using:
SELECT COUNT(*) FROM Orders WHERE OrderDate >= '1980-01-01'
...which may ...