Cannot resolve collation conflict between '' and '' in equal to operation
Collations and tempdb
The tempdb database is built every time SQL Server is started and has the same default collation as the model database. This is typically the same as the default collation of the instance. If you create a user database and specify a different default collation than model, the user database has a different default collation than tempdb. All temporary stored procedures or temporary tables are created and stored in tempdb. This means that all implicit columns in temporary tables and all coercible-default constants, variables, and parameters in temporary stored procedures have collations that are different from comparable objects created in permanent tables and stored procedures.
This could lead to problems with a mismatch in collations between user-defined databases and system database objects. For example, an instance of SQL Server uses the Latin1_General_CS_AS collation and you execute the following statements:
CREATE DATABASE TestDB COLLATE Estonian_CS_AS;
USE TestDB;
CREATE TABLE TestPermTab (PrimaryKey int PRIMARY KEY, Col1 nchar );
In this system, the tempdb database uses the Latin1_General_CS_AS collation with code page 1252, and
TestDB and TestPermTab.Col1 use the Estonian_CS_AS collation with code page 1257. For example:USE TestDB;
GO
-- Create a temporary table with the same column declarations
-- as TestPermTab
CREATE TABLE #TestTempTab (PrimaryKey int PRIMARY KEY, Col1 nchar );
INSERT INTO #TestTempTab
SELECT * FROM TestPermTab;
GO
With the previous example, the tempdb database uses the Latin1_General_CS_AS collation, and
TestDB and TestTab.Col1 use the Estonian_CS_AS collation. For example:SELECT * FROM TestPermTab AS a INNER JOIN #TestTempTab on a.Col1 = #TestTempTab.Col1;
Because tempdb uses the default server collation and
TestPermTab.Col1 uses a different collation, SQL Server returns this error: "Cannot resolve collation conflict between 'Latin1_General_CI_AS_KS_WS' and 'Estonian_CS_AS' in equal to operation."
To prevent the error, you can use one of the following alternatives:
- Specify that the temporary table column use the default collation of the user database, not tempdb. This enables the temporary table to work with similarly formatted tables in multiple databases, if that is required of your system.
CREATE TABLE #TestTempTab (PrimaryKey int PRIMARY KEY, Col1 nchar COLLATE database_default ); - Specify the correct collation for the
#TestTempTabcolumn:CREATE TABLE #TestTempTab (PrimaryKey int PRIMARY KEY, Col1 nchar COLLATE Estonian_CS_AS );
Set or Change the Column Collation
You can override the database collation for char, varchar, text, nchar, nvarchar, and ntext data by specifying a different collation for a specific column of a table and using one of the following:
- The COLLATE clause of CREATE TABLE and ALTER TABLE. For example:
CREATE TABLE dbo.MyTable (PrimaryKey int PRIMARY KEY, CharCol varchar(10) COLLATE French_CI_AS NOT NULL ); GO ALTER TABLE dbo.MyTable ALTER COLUMN CharCol varchar(10)COLLATE Latin1_General_CI_AS NOT NULL; GO - SQL Server Management Studio. For more information, Collation and Unicode Support.
- Using the Column.Collation property in SQL Server Management Objects (SMO).You cannot change the collation of a column that is currently referenced by any one of the following:
- A computed column
- An index
- Distribution statistics, either generated automatically or by the CREATE STATISTICS statement
- A CHECK constraint
- A FOREIGN KEY constraintWhen you work with tempdb, the COLLATE clause includes a database_default option to specify that a column in a temporary table uses the collation default of the current user database for the connection instead of the collation of tempdb.
Collations and text Columns
You can insert or update values in a text column whose collation is different from the code page of the default collation of the database. SQL Server implicitly converts the values to the collation of the column.
Change Collation of a SQL Server Table Column using T-SQL:
First find current column collation:
USE AdventureWorks
GO
Select TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, COLLATION_NAME, DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'dbo'
AND TABLE_NAME = 'col_test'
AND COLUMN_NAME = 'Text'
-------------- Disable all constraints for database
EXEC sp_msforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"
----------------------- Enable all constraints for database
EXEC sp_msforeachtable "ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"
---------To find column name of collation
Select TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME, COLLATION_NAME, DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'dbo'
AND TABLE_NAME = 'col_test
----Change Collation of a SQL Server Table Column:
USE databasename
GO
ALTER TABLE [dbo].[col_test]
ALTER COLUMN Text NVARCHAR(10)
COLLATE SQL_Latin1_General_CP1_CS_AS NULL
To change the database collation
- Connect to the Database Engine.
- From the Standard bar, click New Query.
- Copy and paste the following example into the query window and click Execute. This example shows how to use the COLLATEclause in an ALTER DATABASE statement to change the collation name. Execute the
SELECTstatement to verify the change.
SQL
USE master;
GO
ALTER DATABASE MyOptionsTest
COLLATE French_CI_AS ;
GO
--Verify the collation setting.
SELECT name, collation_name
FROM sys.databases
WHERE name = N'MyOptionsTest';
GO
https://www.mssqltips.com/sqlservertip/3519/changing-sql-server-collation-after-installation/
http://zarez.net/?p=1866
http://sqlusa.com/bestpractices2005/collatedatabasedefault/
