我已经尝试过 mysql ststement dinamically rows to column关注 here带有查询语句:
SET @sql = NULL;
SELECT
GROUP_CONCAT(DISTINCT
CONCAT(
'MAX(CASE WHEN col = ''',
col,
''' THEN val END) as `',
col, '`'
)
)INTO @sql
FROM
(
SELECT A.id_a, D.id_c id_c,
C.students students,
CONCAT(B.`code`, '_', A.id_a) col,
CONCAT(D.value_m, ',', D.value_n) val
FROM table_a A
INNER JOIN table_d D ON A.id_a =D.id_a
INNER JOIN table_b B ON D.id_b=B.id_b
INNER JOIN table_c C ON D.id_c=C.id_c
)dd;
SET @sql = CONCAT('SELECT id_c, students,', @sql, '
FROM(
SELECT A.id_a, D.id_c id_c,
C.students students,
CONCAT(B.`code`, '_', A.id_a) col,
CONCAT(D.value_m, ',', D.value_n) val
FROM table_a A
INNER JOIN table_d D ON A.id_a =D.id_a
INNER JOIN table_b B ON D.id_b=B.id_b
INNER JOIN table_c C ON D.id_c=C.id_c
)dd
GROUP BY id_c'
);
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;
带有结果消息:
Query OK, 0 rows affected
Query OK, 1 row affected
1064 - 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 '', A.id_a) col,
CONCAT(D.value_m, ',', D.value_n) val
FROM table_a A ' at line 1
1064 - 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 'MAX(CASE WHEN col = 'MAT_1' THEN val END) as `MAT_1`,MAX(CASE WHEN col = 'BIO_1'' at line 1
1243 - Unknown prepared statement handler (stmt) given to EXECUTE
1243 - Unknown prepared statement handler (stmt) given to DEALLOCATE PREPARE
我不熟悉这样的sql语句,以及那个SQL QUERY有什么问题
谢谢...
最佳答案
如果您查看代码(并放大):
SET @sql = CONCAT('SELECT id_c, students,', @sql, '
[..]
CONCAT(B.`code`, '_', A.id_a) col,
CONCAT(D.value_m, ',', D.value_n) val
[..]
GROUP BY id_c'
);
您将看到 _
和 ,
是黑色的,而它们作为字符串的一部分应该是红色的。这意味着你的弦在那里“断”了。所以你需要用 ''
转义单引号:
SET @sql = CONCAT('SELECT id_c, students,', @sql, '
[..]
CONCAT(B.`code`, ''_'', A.id_a) col,
CONCAT(D.value_m, '','', D.value_n) val
[..]
GROUP BY id_c'
);
或者对包含单引号的字符串使用双引号:
SET @sql = CONCAT('SELECT id_c, students,', @sql, "
[..]
CONCAT(B.`code`, '_', A.id_a) col,
CONCAT(D.value_m, ',', D.value_n) val
[..]
GROUP BY id_c"
);
现在完整的字符串应该是红色的:-)
关于mysql - GROUP_CONCAT mysql语句错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42289421/