大约有 5,880 项符合查询结果(耗时:0.0237秒) [XML]

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In SQL, what's the difference between count(column) and count(*)?

...column) does not [edit] added this code so that people can run it create table #bla(id int,id2 int) insert #bla values(null,null) insert #bla values(1,null) insert #bla values(null,1) insert #bla values(1,null) insert #bla values(null,1) insert #bla values(1,null) insert #bla values(null,null) se...
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Why do you create a View in a database?

...ews can hide complexity If you have a query that requires joining several tables, or has complex logic or calculations, you can code all that logic into a view, then select from the view just like you would a table. 2. Views can be used as a security mechanism A view can select certain columns an...
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What are best practices for multi-language database design? [closed]

...hat is the best way to create multi-language database? To create localized table for every table is making design and querying complex, in other case to add column for each language is simple but not dynamic, please help me to understand what is the best choose for enterprise applications ...
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How to use index in select statement?

Lets say in the employee table, I have created an index(idx_name) on the emp_name column of the table. 8 Answers ...
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SQL query to find record with ID not in another table

I have two tables with binding primary key in database and I desire to find a disjoint set between them. For example, 6 Ans...
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What are the best practices for using a GUID as a primary key, specifically regarding performance?

I have an application that uses GUID as the Primary Key in almost all tables and I have read that there are issues about performance when using GUID as Primary Key. Honestly, I haven't seen any problem, but I'm about to start a new application and I still want to use the GUIDs as the Primary Keys, b...
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Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?

I have the following table: 4 Answers 4 ...
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SQL statement to get column type

Is there a SQL statement that can return the type of a column in a table? 22 Answers 2...
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MySQL query to get column names?

I'd like to get all of a mysql table's col names into an array in php? 21 Answers 21 ...
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Get Insert Statement for existing row in MySQL

...ut you can get them using mysqldump like Rob suggested. Specify -t to omit table creation. mysqldump -t -u MyUserName -pMyPassword MyDatabase MyTable --where="ID = 10" share | improve this answer ...