删除sql注入

三种方法：第一种针对单个表 第二种针对单个表字段太多的情况（print输出有字数限制） 第三种针对于单个库（最强模式可直接将库中所有表的所有字符串类型字段全部更新）

第一种：直接导出sql语句
declare @curTable varchar(500),
        @FilterStr varchar(500);--过滤字符串 字符串及之后的数据将被替换为空
set  @FilterStr='</title><style>.alx2{';
set  @curTable='users_log_table';        
DECLARE 
    @SQLList varchar(8000),
    @tableName VARCHAR(1000),
    @name VARCHAR(1000),
    @type VARCHAR(1000);
set @SQLList='';
BEGIN
  -- 定义游标.
  DECLARE c_test_main CURSOR FAST_FORWARD FOR
    -- select [dbid],[name] from sysdatabases where dbid>4;--查询数据库名称
    select b.name as tableName,a.name as columnName,c.name as columnType from syscolumns a inner join sysobjects b on a.id=b.id inner join systypes c on a.xtype=c.xtype 

WHERE a.id=OBJECT_ID(N'['+@curTable+']') And c.name not like 'sysname' ORDER BY colid
    
  -- 打开游标.
  OPEN c_test_main;
 
  WHILE 1=1
  BEGIN
    -- 填充数据.
    FETCH NEXT FROM c_test_main INTO @tableName,@name,@type;
    -- 假如未检索到数据，退出循环.
    IF @@fetch_status!= 0 BREAK;
    
    if @type='varchar' or @type='nvarchar' 
        begin
            --select @tableName,@name,@type;
            set @SQLList=@SQLList+';update ['+@tableName+'] set ['+@name+']=replace(['+@name+'],isnull(substring(['+@name+'],  case charindex('''+@FilterStr+''',['+@name+'])  when 0 then len(['+@name+'])+1 else  charindex('''+@FilterStr+''',['+@name+']) end ,len(['+@name+'])),''''),''''); '+(char(10)+char(13));
        end
    else if @type='ntext' or  @type='text' 
        begin
            set @SQLList=@SQLList+';update ['+@tableName+'] set  ['+@name+']=cast(replace(cast(['+@name+'] as varchar(8000)), isnull(substring(cast(['+@name+'] as varchar(8000)),case charindex('''+@FilterStr+''',cast(['+@name+'] as varchar(8000)))  when 0 then len(cast(['+@name+'] as varchar(8000)))+1 else  charindex('''+@FilterStr+''',cast(['+@name+'] as varchar(8000))) end,len(cast(['+@name+'] as varchar(8000)))),''''),'''') as ntext ); '+(char(10)+char(13));
        end 
  END;
  
  -- 关闭游标
  CLOSE c_test_main;
  -- 释放游标.
  DEALLOCATE c_test_main;
END
print @SQLList;