SQL Server的Collate語句需注意什麼？

本文是SQL Server的Collate語句需注意的介紹，下面是該介紹的詳細信息。

整個Script全部在這裡!

我當時就將這段腳本拉進了查詢分析器，一執行，呵呵，根本沒錯啊!那老大為什麼要發這樣的郵件出來呢?於是我又切換了幾個database,也沒有什麼問題，正當我准備測試完這一個database就放棄測試退出的時候，問題來了。錯誤消息如下：

Server: Msg 446, Level 16, State 9, Line 61

Cannot resolve collation conflict for equal to operation.

呵呵，有困難，找警察，咱有難，就找online啦。按下F1,鍵入collation,最後定位至See also中的Collate,查到幫助文件如下(不好意思，我只是將sql server2000 的在線幫助源封不動的復制了一下，當然在我當時沒有看仔細的那一句我變換了顏色，各位朋友也請不要犯同樣的錯誤為好。呵呵)：

COLLATE

A clause that can be applied to a database definition or a column definition to define the collation, or to a character string expression to apply a collation cast.

Syntax

COLLATE < collation_name >

< collation_name > :: =

{ Windows_collation_name } | { SQL_collation_name }

Arguments

collation_name

Is the name of the collation to be applied to the expression, column definition, or database definition. collation_name can be only a specified Windows_collation_name or a SQL_collation_name.

Windows_collation_name

Is the collation name for Windows collation. See Windows Collation Names.

SQL_collation_name

Is the collation name for a SQL collation. See SQL Collation Names.

Remarks

The COLLATE clause can be specified at several levels, including the following:

Creating or altering a database.

You can use the COLLATE clause of the CREATE DATABASE or ALTER DATABASE statement to specify the default collation of the database. You can also specify a collation when you create a database using SQL Server Enterprise Manager. If you do not specify a collation, the database is assigned the default collation of the SQL Server instance.

Creating or altering a table column.

You can specify collations for each character string column using the COLLATE clause of the CREATE TABLE or ALTER TABLE statement. You can also specify a collation when you create a table using SQL Server Enterprise Manager. If you do not specify a collation, the column is assigned the default collation of the database.

You can also use the database_default option in the COLLATE clause to specify that a column in a temporary table use the collation default of the current user database for the connection instead of tempdb.

Casting the collation of an expression.

You can use the COLLATE clause to cast a character expression to a certain collation. Character literals and variables are assigned the default collation of the current database. Column references are assigned the definition collation of the column.  For the collation of an expression, see Collation Precedence.

The collation of an identifier depends on the level at which it is defined. Identifiers of instance-level objects, such as logins and database names, are assigned the default collation of the instance. Identifiers of objects within a database, such as tables, views, and column names, are assigned the default collation of the database. For example, two tables with names differing only in case may be created in a database with case-sensitive collation, but may not be created in a database with case-insensitive collation.

Variables, GOTO labels, temporary stored procedures, and temporary tables can be created when the connection context is associated with one database, and then referenced when the context has been switched to another database. The identifiers for variables, GOTO labels, temporary stored procedures, and temporary tables are in the default collation of the instance.

The COLLATE clause can be applied only for the char, varchar, text, nchar, nvarchar, and ntext data types.

Collations are generally identified by a collation name. The exception is in Setup where you do not specify a collation name for Windows collations, but instead specify the collation designator, and then select check boxes to specify binary sorting or dictionary sorting that is either sensitive or insensitive to either case or accents.

You can execute the system function fn_helpcollations to retrieve a list of all the valid collation names for Windows collations and SQL collations:

SELECT *FROM ::fn_helpcollations()

SQL Server can support only code pages that are supported by the underlying operating system. When you perform an action that depends on collations, the SQL Server collation used by the referenced object must use a code page supported by the operating system running on the computer. These actions can include:

Specifying a default collation for a database when you create or alter the database.

Specifying a collation for a column when creating or altering a table.

When restoring or attaching a database, the default collation of the database and the collation of any char, varchar, and text columns or parameters in the database must be supported by the operating system.

Code page translations are supported for char and varchar data types, but not for text data type. Data loss during code page translations is not reported.

If the collation specified or the collation used by the referenced object, uses a code page not supported by Windows®, SQL Server issues error. For more information, see the Collations section in the SQL Server Architecture chapter of the SQL Server Books Online.

當時，我承認，我確實大致看完了全篇了，心裡明白是排序規則的原因，導致了錯誤信息的出現。使用collate語句強制指定排序規則是可以解決的，於是我在老大的代碼上的每個字串類型的字段後面都加上了 collate Chinese_PRC_CI_AS  ，然後F5運行，faint...，問題照舊。於是改為：collate SQL_Latin1_General_CP1_CI_AS,嗯，問題解決，正當以為就這樣可以解決的時候，我又試了一下沒加之前沒錯的database,faint...,他們出現了同樣的錯誤信息，難道是拆東牆補西牆。不行， 問題沒有解決，於是，我也上QQ群發問了，也不知是因為今天是周末還是什麼原因，總之沒有一個人回答我。最後實在沒有辦法，只好自己再回來看上面那段其實我並不喜歡的幫助啦(因為是英文嘛!呵呵...),當我看到

You can also use the database_default option in the COLLATE clause to specify that a column in a temporary table use the collation default of the current user database for the connection instead of tempdb.

以上就是精品提供的關於SQL Server的Collate語句需注意的內容，希望對大家有所幫助。