我在MySQL过程中使用CONCAT()时遇到问题。
我正在使用MySQL版本:8.0.22
从命令行,CONCAT适用于以下两种情况。因此,在我看来,我应该可以在过程中使用这些格式之一。
root@localhost [mdy_exp_constraints]> SET @primary_color_name = 'yellow';
Query OK, 0 rows affected (0.00 sec)
root@localhost [mdy_exp_constraints]> SELECT CONCAT('Data too short for ', @primary_color_name, ' column.');
+----------------------------------------------------------------+
| CONCAT('Data too short for ', @primary_color_name, ' column.') |
+----------------------------------------------------------------+
| Data too short for yellow column. |
+----------------------------------------------------------------+
1 row in set (0.00 sec)
root@localhost [mdy_exp_constraints]> SET @woof = CONCAT('Data too short for ', @primary_color_name, ' column.');
Query OK, 0 rows affected (0.00 sec)
root@localhost [mdy_exp_constraints]> SELECT @woof;
+-----------------------------------+
| @woof |
+-----------------------------------+
| Data too short for yellow column. |
+-----------------------------------+
1 row in set (0.00 sec)
这是我用来测试程序的数据
CALL mdy_exp_constraints.checkColorsForTooFewChars('red', 'ff');
Query OK, 0 rows affected (0.00 sec)
IN primary_color_value CHAR(2)
。MySQl服务器处理此错误。CALL mdy_exp_constraints.checkColorsForTooFewChars('green', 'fff');
ERROR 1406 (22001): Data too long for column 'primary_color_value' at row 1
CALL mdy_exp_constraints.checkColorsForTooFewChars('blue', 'a');
ERROR 1644 (45000): Data too short for column.
在下面,我定义了我的程序。
CREATE SCHEMA mdy_exp_constraints
DEFAULT CHARACTER SET utf8mb4
COLLATE utf8mb4_0900_ai_ci;
USE mdy_exp_constraints;
DROP PROCEDURE IF EXISTS mdy_exp_constraints.checkColorsForTooFewChars;
SHOW COUNT(*) WARNINGS;
SHOW WARNINGS;
# -- SHOW all PROCEDUREs for the specified database.
SHOW
PROCEDURE STATUS
WHERE
db = 'mdy_exp_constraints'\G
DELIMITER $
CREATE PROCEDURE checkColorsForTooFewChars(
IN primary_color_name VARCHAR(32),
IN primary_color_value CHAR(2)
)
BEGIN
DECLARE required_str_length TINYINT;
SET required_str_length = 2;
IF CHAR_LENGTH(primary_color_value) < required_str_length THEN
SIGNAL SQLSTATE '45000'
SET MESSAGE_TEXT = CONCAT('Data too short for ', primary_color_name, ' column.');
-- SET MESSAGE_TEXT = 'Data too short for column.';
END IF;
END $
DELIMITER ;
这是我收到的错误。
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '('Data too short for ', primary_color_name, ' column.');
END IF' at line 11
如果我注释掉包含CONCAT行()和未注释不包含CONCAT(),这个程序在运行时对测试数据......除了,它不会报告工作线primary_color_name
,这是什么我想为此做。
谢谢,
麦克风
发生错误,因为SET MESSAGE_TEXT
不接受表达式。
DELIMITER $
CREATE PROCEDURE checkColorsForTooFewChars(
IN primary_color_name VARCHAR(32),
IN primary_color_value CHAR(2)
)
BEGIN
DECLARE required_str_length TINYINT;
SET required_str_length = 2;
IF CHAR_LENGTH(primary_color_value) < required_str_length THEN
SET @errorMsg = CONCAT('Data too short for ', primary_color_name, ' column.');
SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = @errorMsg;
END IF;
END $
DELIMITER ;
本文收集自互联网,转载请注明来源。
如有侵权,请联系[email protected] 删除。
我来说两句