sql - 如何在 MsSQL 中进行简单的“查找和替换”？

Question

问题很容易解释。我想做一个简单的查找和替换，就像你在我的数据库列中的数据的文本编辑器中一样（这是 MS Windows server 2003 上的 MsSQL）

Answer 1

以下查询将每个a字符替换为一个b字符。

UPDATE 
    YourTable
SET 
    Column1 = REPLACE(Column1,'a','b')
WHERE 
    Column1 LIKE '%a%'

这不适用于 SQL Server 2003。

Answer 2

像这样：

BEGIN TRANSACTION; 
UPDATE table_name
  SET column_name=REPLACE(column_name,'text_to_find','replace_with_this'); 
COMMIT TRANSACTION;

示例：将 <script... 替换为 <a ... 以消除 javascript 漏洞

BEGIN TRANSACTION; UPDATE testdb
SET title=REPLACE(title,'script','a'); COMMIT TRANSACTION;

Answer 3

这为我指明了正确的方向，但我有一个源自 MSSQL 2000 的数据库，并且仍在使用ntext我要替换的列的数据类型。当您尝试在该类型上运行 REPLACE 时，您会收到以下错误：

参数数据类型 ntext 对于替换函数的参数 1 无效。

如果您的列数据适合，最简单的解决nvarchar方法是在替换期间强制转换列。从接受的答案中借用代码：

UPDATE YourTable
SET Column1 = REPLACE(cast(Column1 as nvarchar(max)),'a','b')
WHERE Column1 LIKE '%a%'

这对我来说非常有效。感谢这个论坛帖子，我找到了修复程序。希望这对其他人有帮助！

Answer 4

以下将在您连接到的实例上的每个表上的每个数据库（不包括系统数据库）中查找并替换一个字符串：

只需更改'Search String'为您寻求'Replace String'的任何内容以及您想要替换的任何内容。

--Getting all the databases and making a cursor
DECLARE db_cursor CURSOR FOR  
SELECT name 
FROM master.dbo.sysdatabases 
WHERE name NOT IN ('master','model','msdb','tempdb')  -- exclude these databases

DECLARE @databaseName nvarchar(1000)
--opening the cursor to move over the databases in this instance
OPEN db_cursor
FETCH NEXT FROM db_cursor INTO @databaseName   

WHILE @@FETCH_STATUS = 0   
BEGIN
    PRINT @databaseName
    --Setting up temp table for the results of our search
    DECLARE @Results TABLE(TableName nvarchar(370), RealColumnName nvarchar(370), ColumnName nvarchar(370), ColumnValue nvarchar(3630))

    SET NOCOUNT ON

    DECLARE @SearchStr nvarchar(100), @ReplaceStr nvarchar(100), @SearchStr2 nvarchar(110)
    SET @SearchStr = 'Search String'
    SET @ReplaceStr = 'Replace String'
    SET @SearchStr2 = QUOTENAME('%' + @SearchStr + '%','''')

    DECLARE @TableName nvarchar(256), @ColumnName nvarchar(128)
    SET  @TableName = ''

    --Looping over all the tables in the database
    WHILE @TableName IS NOT NULL
    BEGIN
        DECLARE @SQL nvarchar(2000)
        SET @ColumnName = ''
        DECLARE @result NVARCHAR(256)
        SET @SQL = 'USE ' + @databaseName + '
            SELECT @result = MIN(QUOTENAME(TABLE_SCHEMA) + ''.'' + QUOTENAME(TABLE_NAME))
            FROM    [' + @databaseName + '].INFORMATION_SCHEMA.TABLES
            WHERE       TABLE_TYPE = ''BASE TABLE'' AND TABLE_CATALOG = ''' + @databaseName + '''
                AND QUOTENAME(TABLE_SCHEMA) + ''.'' + QUOTENAME(TABLE_NAME) > ''' + @TableName + '''
                AND OBJECTPROPERTY(
                        OBJECT_ID(
                            QUOTENAME(TABLE_SCHEMA) + ''.'' + QUOTENAME(TABLE_NAME)
                                ), ''IsMSShipped''
                                ) = 0'
        EXEC master..sp_executesql @SQL, N'@result nvarchar(256) out', @result out

        SET @TableName = @result
        PRINT @TableName

        WHILE (@TableName IS NOT NULL) AND (@ColumnName IS NOT NULL)
        BEGIN
            DECLARE @ColumnResult NVARCHAR(256)
            SET @SQL = '
                SELECT @ColumnResult = MIN(QUOTENAME(COLUMN_NAME))
                FROM    [' + @databaseName + '].INFORMATION_SCHEMA.COLUMNS
                WHERE       TABLE_SCHEMA    = PARSENAME(''[' + @databaseName + '].' + @TableName + ''', 2)
                    AND TABLE_NAME  = PARSENAME(''[' + @databaseName + '].' + @TableName + ''', 1)
                    AND DATA_TYPE IN (''char'', ''varchar'', ''nchar'', ''nvarchar'')
                    AND TABLE_CATALOG = ''' + @databaseName + '''
                    AND QUOTENAME(COLUMN_NAME) > ''' + @ColumnName + ''''
            PRINT @SQL
            EXEC master..sp_executesql @SQL, N'@ColumnResult nvarchar(256) out', @ColumnResult out
            SET @ColumnName = @ColumnResult 

            PRINT @ColumnName

            IF @ColumnName IS NOT NULL
            BEGIN
                INSERT INTO @Results
                EXEC
                (
                    'USE ' + @databaseName + '
                    SELECT ''' + @TableName + ''',''' + @ColumnName + ''',''' + @TableName + '.' + @ColumnName + ''', LEFT(' + @ColumnName + ', 3630) 
                    FROM ' + @TableName + ' (NOLOCK) ' +
                    ' WHERE ' + @ColumnName + ' LIKE ' + @SearchStr2
                )
            END
        END
    END

    --Declaring another temporary table
    DECLARE @time_to_update TABLE(TableName nvarchar(370), RealColumnName nvarchar(370))

    INSERT INTO @time_to_update
    SELECT TableName, RealColumnName FROM @Results GROUP BY TableName, RealColumnName

    DECLARE @MyCursor CURSOR;
    BEGIN
        DECLARE @t nvarchar(370)
        DECLARE @c nvarchar(370)
        --Looping over the search results   
        SET @MyCursor = CURSOR FOR
        SELECT TableName, RealColumnName FROM @time_to_update GROUP BY TableName, RealColumnName

        --Getting my variables from the first item
        OPEN @MyCursor 
        FETCH NEXT FROM @MyCursor 
        INTO @t, @c

        WHILE @@FETCH_STATUS = 0
        BEGIN
            -- Updating the old values with the new value
            DECLARE @sqlCommand varchar(1000)
            SET @sqlCommand = '
                USE ' + @databaseName + '
                UPDATE [' + @databaseName + '].' + @t + ' SET ' + @c + ' = REPLACE(' + @c + ', ''' + @SearchStr + ''', ''' + @ReplaceStr + ''') 
                WHERE ' + @c + ' LIKE ''' + @SearchStr2 + ''''
            PRINT @sqlCommand
            BEGIN TRY
                EXEC (@sqlCommand)
            END TRY
            BEGIN CATCH
                PRINT ERROR_MESSAGE()
            END CATCH

            --Getting next row values
            FETCH NEXT FROM @MyCursor 
            INTO @t, @c 
        END;

        CLOSE @MyCursor ;
        DEALLOCATE @MyCursor;
    END;

    DELETE FROM @time_to_update
    DELETE FROM @Results

    FETCH NEXT FROM db_cursor INTO @databaseName
END   

CLOSE db_cursor   
DEALLOCATE db_cursor

注意：这不是理想的，也不是优化的

Answer 5

如果您使用的是 SQL Server 2005 或更高版本，那么http://www.sqlsharp.com/上还有一个 CLR 库，它提供了字符串和 RegEx 函数的 .NET 实现，根据您的数据量和类型，这些函数可能是更易于使用，在某些情况下，.NET 字符串操作函数可能比 T-SQL 更有效。