求教mysql存储过程问题
获取数据表字段列表的存储过程：
DELIMITER $$
DROP PROCEDURE IF EXISTS VAR$$

CREATE DEFINER='root'@'localhost' PROCEDURE VAR(IN tablename VARCHAR(50))
BEGIN
SET @sql=CONCAT('select column_name from information_schema.columns where
table_name=',tablename);
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END$$

DELIMITER ;

调用时CALL VAR('fruits');
总显示unkonwn column 'fruits' in 'where clause'

求解。

[解决办法]
DELIMITER $$
DROP PROCEDURE IF EXISTS VAR$$

CREATE DEFINER='root'@'localhost' PROCEDURE VAR(IN tablename VARCHAR(50))
BEGIN
SET @SQL=CONCAT('select column_name from information_schema.columns where
table_name=\'',tablename,'\'');
PREPARE stmt FROM @SQL;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END$$

DELIMITER ;
[解决办法]

CREATE DEFINER='root'@'localhost' PROCEDURE VAR(IN tablename VARCHAR(50))
BEGIN
SET @sql=CONCAT('select column_name from information_schema.columns where
table_name=',tablename);
select @sql
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END$$

DELIMI


输出你的@sql的内容你就明白了。