A weird error in Matlab with MySQL - mysql

Question

I have two tables named t1 and t2, which content list as following:
mysql> use test;
Database changed
mysql> select * from t1;
+----+------+
| id | val |
+----+------+
| 1 | 100 |
| 2 | 200 |
+----+------+
2 rows in set (0.00 sec)
mysql> select * from t2;
+----+-------+
| id | val |
+----+-------+
| -1 | -1000 |
| 1 | 1000 |
| 3 | 3000 |
+----+-------+
3 rows in set (0.00 sec)
There is a sql statement run in mysql command with on problem:
mysql> create or replace view iid as select id from t1 union select id from t2;select iid.id,t1.val,t2.val from iid left join t1 on iid.id=t1.id left join t2 on iid.id=t2.id;
Query OK, 0 rows affected (0.07 sec)
+----+------+-------+
| id | val | val |
+----+------+-------+
| 1 | 100 | 1000 |
| 2 | 200 | NULL |
| -1 | NULL | -1000 |
| 3 | NULL | 3000 |
+----+------+-------+
4 rows in set (0.00 sec)
While it run in matlab with a error:
>> sqlCmd = ['create or replace view iid as select id from t1 union select id from t2;',...
'select iid.id,t1.val,t2.val from iid',...
' left join t1 on iid.id=t1.id',...
' left join t2 on iid.id=t2.id'];
conn = database('test','root','198471',...
'com.mysql.jdbc.Driver','jdbc:mysql://127.0.0.1:3306/test');
>> curs = exec(conn,sqlCmd);
>> curs.Message
ans =
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 'select iid.id,t1.val,t2.val from iid left join t1 on iid.id=t1.id left join t2 o' at line 1
>> curs = exec(conn,'select * from t1');
>> curs = fetch(curs);
>> curs.Data
ans =
1 100
2 200
>> sqlCmd
I'm a pure newbie of SQL, and I have no idea for this error message.
Any help would be appreciated.

Answer 1

It would appear that Matlab treats each string in your sqlCmd matrix as a separate SQL statment. As you are breaking up the queries into string portions this will not work, because each not every portion is a valid standalone SQL statement. As the comment above suggests, you may need to search for a setting that allows this. Alternatively you could try to rewrite your SQL into a single string just like you did with mysql:
sqlCmd = 'create or replace view iid as select id from t1 union select id from t2;select iid.id,t1.val,t2.val from iid left join t1 on iid.id=t1.id left join t2 on iid.id=t2.id;';
curs = exec(conn,sqlCmd);
This should at least run your query without error. If you have not done so already, take a look at the mathworks documentation for exec http://www.mathworks.co.uk/help/toolbox/database/ug/exec.html