SQL Server：如何在表的所有varchar列上执行Rtrim

Question

I have over 30 columns in my table (sql server 2008). Columns type are varchar(x). I know that in every column there is two extra spaces at the end of column value. How to use rtrim function for all columns and save this modification into this existing table?

Edit: is there a way to do it using stored procedure or cursor where I don't have to manually declare all columns?

Answer 1

For a generic approach, you can use a script like this to generate the statement for you, for a given table (useful if you have many columns!):

DECLARE @SQL VARCHAR(MAX)
DECLARE @TableName NVARCHAR(128)
SET @TableName = 'YourTableName'

SELECT @SQL = COALESCE(@SQL + ',[', '[') + 
              COLUMN_NAME + ']=RTRIM([' + COLUMN_NAME + '])'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = @TableName
    AND DATA_TYPE = 'varchar'

SET @SQL = 'UPDATE [' + @TableName + '] SET ' + @SQL
PRINT @SQL

That will just print the SQL statement out. You can either then copy + run the statement, or just EXECUTE(@SQL) . This is untested, so just try it out on a test table first :)

Answer 2

UPDATE xxx
  SET col1 = RTRIM(col1),
      col2 = RTRIM(col2),
      col3 = RTRIM(col3),
      ...

Answer 3

We can have stored procedure to trim specific table under specific schema . If we have different schema names other than default dbo schema, it is better to use this SP by passing schema name and table name. This performs both LTRIM and RTRIM . This SP would check char , nchar , varchar , nvarchar columns.

CREATE PROCEDURE [dbo].[TrimAllColumnsOfTable] @SchemaName Varchar(100),@TableName Varchar(100)
AS
BEGIN

DECLARE @SQL VARCHAR(MAX)
SELECT @SQL = COALESCE(@SQL + ',[', '[') +
              COLUMN_NAME + ']=LTRIM(RTRIM([' + COLUMN_NAME + ']))'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = @SchemaName AND TABLE_NAME = @TableName AND DATA_TYPE Like '%char%'

SET @SQL = 'UPDATE [' + @SchemaName + '].[' + @TableName + '] SET ' + @SQL

EXEC (@SQL)

END

USAGE: [TrimAllColumnsOfTable] 'SchemaName','TableName'

Answer 4

It is perfect... But remember to put also the where clause:

COLUMNPROPERTY(OBJECT_ID(TABLE_SCHEMA+'.'+TABLE_NAME),COLUMN_NAME,'IsComputed') = 0

Ohterwise you will get an error if the table has a computed column of "%char%" type!

Answer 5

The accepted answer works well. I ran into an issue with a temp table being named the same name. You can add

and TABLE_SCHEMA = 'dbo'

And that will get rid of collision on table names.