フォローアップ - アーカイブストアドプロシージャ

Question

私が始めた以前のスレッドはArchival stored proceduresでしたが、これはそれに続く質問です。私は何を持っていることは、私は前月から古い列を削除したい場合しかし、手続きがエラーで右が吹くまで、アクティブなデータベースの正確なコピーを作る作業ストアドプロシージャである：ここでは

Msg 102, Level 15, State 1, Line 3
Incorrect syntax near 'D201609__'.

declare @tablename varchar(500) 
declare @sql varchar(5000) 
declare @idname varchar(50) 
declare @tablearchive varchar(500) 
declare @lastmonth nvarchar(MAX) 

SET @lastmonth = 'D' + cast(year(getdate()) as char(4)) + right('0' + cast(month(getdate())-1 as varchar), 2) + '__' 
--Select all the tables which you want to make in archive 

declare tableCursor cursor FAST_FORWARD FOR 
    SELECT table_name 
    FROM INFORMATION_SCHEMA.TABLES 
    WHERE table_name = 'CVECountsByDate' 

--Put your condition, if you want to filter the tables 
--like '%TRN_%' and charindex('Archive',table_name) = 0 and charindex('ErrorLog',table_name) = 0 
--Open the cursor and iterate till end 
OPEN tableCursor 
FETCH NEXT FROM tableCursor INTO @tablename  

WHILE @@FETCH_STATUS = 0 
BEGIN 
    set @tablearchive = @tablename+'_Archive' 

    --check for the table exists, not, create it 
    IF not EXISTS (SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_TYPE='BASE TABLE' AND TABLE_NAME= @tablearchive) 
    BEGIN 
     SET @sql = 'select * into ' + @tablearchive +' from '+ @tablename +' where 1=2' 
     EXEC(@sql) 
    END 

    --check the structure is same, if not, create it 
    IF exists (select column_name from 
      INFORMATION_SCHEMA.COLUMNS where TABLE_NAME=@tablename and column_name not in (select column_name from INFORMATION_SCHEMA.COLUMNS 
      where TABLE_NAME=@tablearchive)) 
    BEGIN 
     SET @sql = 'drop table ' + @tablearchive 
     EXEC(@sql) 

     SET @sql = 'select * into ' + @tablearchive +' from '+ @tablename +' where 1=2' 
     EXEC(@sql) 
    END 

    --Check if the table contains, identify column,if yes, then it should be handled in different way 
    --You cannot remove the identity column property through T-SQL 
    --Since the structure of both tables are same, the insert fails, as it cannot insert the identity column 
    --value in the archive table 
    IF EXISTS(SELECT *  FROM information_schema.tables  WHERE table_name = @tablename AND OBJECTPROPERTY(OBJECT_ID(TABLE_NAME), 
      'TableHasIdentity') != 0) 
    BEGIN 
     --Select the identity column name automatically    
     select @idname = column_name 
     from information_schema.columns 
     where columnproperty(object_id(table_name), column_name, 'isidentity') = 1 
      and table_name = @tablearchive 

     --Remove the column 
     SET @sql = 'ALTER TABLE ' + @tablearchive + ' DROP COLUMN ' + @idname 
     EXEC(@sql) 

     --Create the column name again (not as identity) 
     --archive table does require identity column 
     SET @sql = 'ALTER TABLE ' + @tablearchive + ' ADD ' + @idname+ ' INT' 
     EXEC(@sql) 
    END 

    SET @sql = 'insert into ' + @tablearchive +' select * from '+ @tablename 
    EXEC(@sql) 

    FETCH NEXT FROM tableCursor INTO @tablename 

    declare @PrevMonth nvarchar(MAX) = 'D' + cast(year(getdate()) as char(4)) + right('0' + cast(month(getdate())-1 as varchar), 2) + '__' 
    DECLARE @DynSql nvarchar(MAX) = 'ALTER TABLE ' + @tablename + ' DROP COLUMNS IF EXISTS 
    (SELECT COLUMN_NAME Columns FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = ' + @tablename + ' 
AND COLUMN_NAME LIKE ' + @PrevMonth + '' 

    SELECT (@DynSql) 
    EXEC(@DynSql) 
END 

CLOSE tableCursor 
DEALLOCATE tableCursor 

正確にどのようにして私のprocの列削除部分を機能させることができますか？どうやら、私は道を見つめ

Answer 1

私のクエリがあまりにも長い間読み：これは、実際にこのような出力を持っている必要があり

ALTER TABLE CVECountsByDate DROP COLUMNS IF EXISTS (SELECT COLUMN_NAME 
Columns FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = CVECountsByDate AND COLUMN_NAME LIKE 'D201609__' 

：

ALTER TABLE CVECountsByDate DROP COLUMNS IF EXISTS (SELECT COLUMN_NAME 
Columns FROM INFORMATION_SCHEMA.COLUMNS 
WHERE TABLE_NAME = 'CVECountsByDate' AND COLUMN_NAME LIKE 'D201609__' 

私は引用符でテーブル名を囲むのを忘れていました。そして、はい、私はそれが私の上に浮かんだとき、私の額の真ん中に赤い手のプリントを持っています。

次のようにクエリ自体は読む：

DECLARE @DynSql nvarchar(MAX) = 'ALTER TABLE CVECountsByDate DROP 
    COLUMNS IF EXISTS (SELECT COLUMN_NAME Columns FROM 
    INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = '''CVECountsByDate''' AND 
    COLUMN_NAME LIKE ''' + @PrevYear + ''')'