大约有 37,000 项符合查询结果(耗时:0.0403秒) [XML]

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The multi-part identifier could not be bound

... FROM (a, b) LEFT JOIN dkcd ON … WHERE … that is, the combination of tables a and b is joined with the table dkcd. In fact, what's happening is SELECT … FROM a, (b LEFT JOIN dkcd ON …) WHERE … that is, as you may already have understood, dkcd is joined specifically against b and onl...
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What is the reason not to use select *?

...nt, the SQL execution engine will error if that column is removed from the table and the query is executed. You can more easily scan code where that column is being used. You should always write queries to bring back the least amount of information. As others mention if you use ordinal column access...
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Parse JSON in TSQL

...le Talk website that outlines how to take a JSon string and output it into tables and columns that can be queried. This is for SQL Server 2016: https://www.simple-talk.com/sql/learn-sql-server/json-support-in-sql-server-2016/ – codeaf Jul 28 '16 at 18:10 ...
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Check if value exists in Postgres array

... how can I search for a column from another table to have a value in the array? e.g. select * from beers where style_id in (select preferences from users where id=1) limit 1; style_id is an integer data type; preferences is integer[] I get this error ERROR: operato...
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Compare two MySQL databases [closed]

... sets, etc. mysqldump --opt --compact --skip-extended-insert -u user -p db table > file.sql – zanlok Mar 6 '12 at 21:53 ...
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How to move a model between two Django apps (Django 1.7)

...on(migrations.Migration): database_operations = [migrations.AlterModelTable('TheModel', 'newapp_themodel')] state_operations = [migrations.DeleteModel('TheModel')] operations = [ migrations.SeparateDatabaseAndState( database_operations=database_operations, state_...
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Is there any performance gain in indexing a boolean field?

...is is not entirely correct, without an index mySql needs to scan the whole table to find the relevant rows. – ilanco May 9 '12 at 22:04 4 ...
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How to customize the background color of a UITableViewCell?

...ike to customize the background (and maybe the border too) of all of the UITableViewCells within my UITableView. So far I have not been able to customize this stuff, so I have a bunch of white background cells which is the default. ...
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How to drop columns using Rails migration

What's the syntax for dropping a database table column through a Rails migration? 20 Answers ...
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Remove specific characters from a string in Python

... Strings in Python are immutable (can't be changed). Because of this, the effect of line.replace(...) is just to create a new string, rather than changing the old one. You need to rebind (assign) it to line in order to have that variable take the new...