sql Вывестивсеколонки，значениякоторыхвсехзаписейNULL

Posted 2021-05-13

/* Просто выводим колонки */

declare @col varchar(255), @cmd varchar(max) 

DECLARE getinfo cursor for 
SELECT c.name FROM sys.tables t JOIN sys.columns c ON t.Object_ID = c.Object_ID WHERE t.Name = 'Ingram' 

OPEN getinfo 
  FETCH NEXT FROM getinfo into @col 
    WHILE @@FETCH_STATUS = 0
      BEGIN 
        SELECT @cmd = '
          IF NOT EXISTS (SELECT top 1 * FROM Ingram WHERE [' + @col + '] IS NOT NULL) 
          BEGIN 
            print ''' + @col + ''' 
          END' 
    EXEC(@cmd) 
  FETCH NEXT FROM getinfo into @col 
END
CLOSE getinfo

DEALLOCATE getinfo


/* Удаляем колонки */
declare @col varchar(255), @cmd varchar(max) 

DECLARE getinfo cursor for 
SELECT c.name FROM sys.tables t JOIN sys.columns c ON t.Object_ID = c.Object_ID WHERE t.Name = 'Ingram' 

OPEN getinfo 
  FETCH NEXT FROM getinfo into @col 
    WHILE @@FETCH_STATUS = 0
      BEGIN 
        SELECT @cmd = '
          IF NOT EXISTS (SELECT top 1 * FROM Ingram WHERE [' + @col + '] IS NOT NULL) 
          BEGIN 
            ALTER TABLE %TABLE_NAME% DROP COLUMN ' + @col + ' 
          END' 
    EXEC(@cmd) 
  FETCH NEXT FROM getinfo into @col 
END
CLOSE getinfo

DEALLOCATE getinfo