在mysql中创建临时表时出错

Question

I am facing difficulty in creating temporary table in mysql.

I have a stored procedure i am creating some sql statement i need to create the sql statement output as a temporary table in my sql. Here is my procedure. any body help me please?

DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `new_procedure`()
BEGIN

SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'MAX(CASE WHEN workspaceid = ''',
      workspaceid,
      ''' then "''''" ELSE NULL end) AS ',
      CONCAT('`',workspaceid,'`')
    )
  ) INTO @sql
FROM sms.hotelings;

SET @sql = CONCAT('SELECT t.Time, ', @sql, ' 
                   FROM sms.hotelings h, sms.hotelingtime t 
                   GROUP BY t.Time');

-- PREPARE stmt FROM @sql;
-- EXECUTE stmt;
-- DEALLOCATE PREPARE stmt;

CREATE TEMPORARY TABLE IF NOT EXISTS table2 AS @sql;
select * from table2
drop temporary table table2;
END

I want to create a temporary table using my @sql statement.

Thanks in advance.

Answer 1

You have to use PREPARE if you want to use a dynamic statement

SET @sql = CONCAT('CREATE TEMPORARY TABLE IF NOT EXISTS table2 AS SELECT t.Time, ', @sql, ' 
                   FROM sms.hotelings h, sms.hotelingtime t 
                   GROUP BY t.Time');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
SELECT * FROM table2;
DROP TEMPORARY TABLE table2;