大约有 47,000 项符合查询结果(耗时:0.0611秒) [XML]

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IN vs OR in the SQL WHERE Clause

...h are nearly instant. When the column is not indexed I got these results: SELECT COUNT(*) FROM t_inner WHERE val IN (1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000); 1 row fetched in 0.0032 (1.2679 seconds) SELECT COUNT(*) FROM t_inner WHERE val = 1000 OR val = 2000 OR val = 3000 OR val = 40...
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Reason for Column is invalid in the select list because it is not contained in either an aggregate f

...c 1 def 1 ghi 2 jkl 2 mno 2 pqr And I do the following query: SELECT a, b FROM T GROUP BY a The output should have two rows, one row where a=1 and a second row where a=2. But what should the value of b show on each of these two rows? There are three possibilities in each case, and no...
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Creating a comma separated list from IList or IEnumerable

...var PurchaseBooks = AmazonContainer.Where(p => p.Author == "Jon Skeet").Select(); – Zachary Scott Oct 31 '10 at 16:26 3 ...
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Does Entity Framework Code First support stored procedures?

...ContextAdapter)this) .ObjectContext.ExecuteStoreQuery<Customer>("select * from customers"); Replace the "select" statement with a stored proc, and there you go. As for your other question: Yes, unfortunately your s.p.'s will get clobbered. You may need to add the "CREATE PROCEDURE" st...
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Regex match everything after question mark?

... for something like this? Topics: code, programming, design So I want to select the colon and look behind as far as the cpaital T of topics and fowards to the end on the line? (in this case end of the line is "design". – Mark Dec 11 '10 at 21:36 ...
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Add 2 hours to current time in MySQL?

... SELECT * FROM courses WHERE DATE_ADD(NOW(), INTERVAL 2 HOUR) > start_time See Date and Time Functions for other date/time manipulation. share ...
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How do you copy and paste into Git Bash

... With QuickEdit on this becomes pretty easy: select, Enter, Insert – gphilip Feb 10 '14 at 8:49 3 ...
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Removing fields from struct or hiding them in JSON Response

...ending back to the caller. I'd now like to allow the caller to be able to select the specific fields they would like returned by passing in a "fields" GET parameter. ...
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Two single-column indexes vs one two-column index in MySQL?

... the statement I provided. Additionally, MySQL can only use one index per SELECT so a covering index would be the best means of optimizing your queries. share | improve this answer | ...
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Reading CSV file and storing values into an array

... LINQ way: var lines = File.ReadAllLines("test.txt").Select(a => a.Split(';')); var csv = from line in lines select (from piece in line select piece); ^^Wrong - Edit by Nick It appears the original answerer was attempting to populate csv with a...