字符串 – SQL Server将表内容转换为合并语句?

前端之家收集整理的这篇文章主要介绍了字符串 – SQL Server将表内容转换为合并语句?前端之家小编觉得挺不错的,现在分享给大家,也给大家做个参考。
我有一个在“位置A”中更改的查找数据表,我需要更新“位置B”中相同的命名表.我想,如果我有一种方式逐行读取表格(80k行)到一个正确格式的字符串,并用合并语句(“将表转换为CTE”)创建一个输出文件,那么我可以有一些光滑的东西.

赞赏这个想法的所有想法(或者那些已经做过类似事情的人的指针).谢谢.我正在使用sql Server Express 2012.

解决方法

我使用这个帮助脚本来管理环境之间的小型查找表. 80k行不算太大,但并不重要.康拉德为移动大量数据制定了坚实的计划.

如果你选择去生成的合并路由,希望这可以帮助你:

declare @TableName nvarchar(128) = 'dbo.YourTable';

--// do not modify
set nocount on; 

if  (   isnull(parsename(@TableName,1),'') = '' or
        isnull(parsename(@TableName,2),'') = ''
    )
begin
    raiserror('@TableName should be in form of owner.object (dbo.Yak). Cannot continue.',16,1,@TableName);
    return;
end
if object_id(@TableName) is null
begin
    raiserror('Table [%s] not found. Cannot continue.',@TableName);
    return;
end
if objectproperty(object_id(@TableName),N'TableHasPrimaryKey') = 0
begin
    raiserror('Table [%s] has no primary key defined. Cannot continue.',@TableName);
    return;
end

declare @output varchar(max)='',@return int,@sql varchar(max) = '',@list varchar(max) = '',@exec nvarchar(max),@Cols varchar(max)='',@sCols varchar(max)='',@aCols varchar(max)='',@pCols varchar(max)='',@uCols varchar(max)='',@b char(1) = char(13),@t char(1) = char(9);

select  @exec = isnull(@exec + '+' + @b,'') + ''','' +' +
        case 
            when c.data_type in ('uniqueidentifier') 
                then @t + '''''+isnull('''''''' + convert(varchar(50),' + c.column_name + ') + '''''''',''null'')'
            when c.data_type in ('xml') 
                then @t + '''''+isnull('''''''' + convert(varchar(max),''null'')'
            when c.data_type in ('char','nchar','varchar','nvarchar','sysname') 
                then @t + '''''+isnull('''''''' + replace(' + c.column_name + ','''''''','''''''''''') + '''''''',''null'')'
            when c.data_type in ('datetime','date') 
                then @t + '''''+isnull('''''''' + convert(varchar,' + c.column_name + ',121)+'''''''',''null'') '
            when c.data_type in ('tinyint','int','float','numeric','decimal','smallmoney','money','bit','smallint','real','bigint') 
                then @t + '''''+isnull(convert(varchar,' + c.column_name + '),''null'')' 
            else ''' ** data type [' + c.data_type + '] not supported **'''
        end,@Cols = @Cols + ','+quotename(c.column_name,'['),@sCols = @sCols + ',s.'+quotename(c.column_name,'[')
from    information_schema.columns c
where   c.table_name = parsename(@TableName,1) and
        c.table_schema = parsename(@TableName,2)
order 
by      c.ordinal_position

-- stage primary key columns
declare @pks table (c varchar(100),o int);
insert into @pks (c,o)
    select  kcu.column_name,kcu.ordinal_position
    from    information_schema.table_constraints tc
    join    information_schema.key_column_usage kcu on
            tc.table_name = kcu.table_name and
            tc.constraint_name = kcu.constraint_name
    where   tc.table_name = parsename(@TableName,1) and
            tc.table_schema = parsename(@TableName,2) and
            tc.constraint_type = 'PRIMARY KEY';

-- build primary key columns (1=1 to ease support of composite PKs)
set @pCols = '1=1'           
select  @pCols = @pCols + ' and '+isnull('t.'+quotename(c,'[') + ' = ' + 's.'+quotename(c,'')
from    @pks    
order
by      o;

-- build update columns,do not update identities or pks
select  @aCols = @aCols + ','+quotename(c.[name],'[') + ' = s.' + quotename(c.[name],'[')
from    sys.columns c
where   object_id = object_id(@TableName) and
        [name] not in (select c from @pks) and
        columnproperty(object_id(@TableName),c.[name],'IsIdentity ') = 0;

-- script the data out as table value constructors
select  @exec = 'set nocount on; Select ' + @b + '''(' + ''' + ' + @b + stuff(@exec,3,'') + '+'')''' + @b + 'from ' + @TableName,@Cols = stuff(@Cols,''),@sCols = stuff(@sCols,@aCols = stuff(@aCols,'');

declare @tab table (val varchar(max));
declare @Values varchar(max);
insert into @tab
    exec(@exec);

if not exists(select 1 from @tab)
begin
    raiserror('Table %s is valid but empty. Populate it before running this helper.',@TableName);
    return
end

select @Values = stuff(cast((select ','+ @b + val from @tab for xml path('')) as xml).value('.','varchar(max)'),2,'');

-- build the merge statement
set @output +=  @b+'--'+@TableName+replicate('-',98-len(@TableName))+@b+replicate('-',100)+@b;
set @output +=  'set nocount on;'+@b
if objectproperty(object_id(@TableName),'TableHasIdentity') = 1 
    set @output += 'set identity_insert [dbo].[' + @TableName + '] on;'+@b;
set @output +=  ';with cte_data('+@Cols+')'+@b+'as (select * from (values'+@b+'--'+replicate('/',98) + @b +@Values+ @b +'--'+replicate('\',98)+ @b +')c('+@Cols+'))'+@b;
set @output +=  'merge' + @t + '['+parsename(@TableName,2)+'].[' + parsename(@TableName,1) + '] as t' + @b + 'using' + @t + 'cte_data as s'+@b;
set @output +=  'on' + replicate(@t,2) + @pCols+@b;
set @output +=  'when matched then' + @b+@t + 'update set'+ @b+@t + @aCols+@b;
set @output +=  'when not matched by target then'+@b;
set @output +=  @t+'insert(' + @Cols + ')'+@b;
set @output +=  @t+'values(' + @sCols + ')'+@b;
set @output +=  'when not matched by source then' + @b+@t+ 'delete;'+@b;
if objectproperty(object_id(@TableName),'TableHasIdentity') = 1 
    set @output += 'set identity_insert [dbo].[' + @TableName + '] off;'

--output the statement as xml (to overcome mgmt studio limitations)
select s as [output] from (select @output)d(s) for xml path('');
return;

猜你在找的MsSQL相关文章