Mysql syntax error : deleting records

Question

I have written this code inside a servlet to delete certain records from three tables.

Note: two of these tables are myisam table for Full-text search reason and other one is innodb table.

int id = Integer.parseInt(request.getParameter("id"));
try {
  Statement stmt = conn.createStatement();
  stmt.executeUpdate("DELETE FROM proposal, suitable_for,skill_need WHERE proposal_id="
                     +id);

I get the following error. I cant see any syntax error in the query I have write

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: 
  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 'where proposal_id=12' at line 1
at sun.reflect.GeneratedConstructorAccessor14.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1052)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4096)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4028)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2677)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1748)
at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1665)
at org.apache.tomcat.dbcp.dbcp.DelegatingStatement.executeUpdate(DelegatingStatement.java:228)
at org.apache.tomcat.dbcp.dbcp.DelegatingStatement.executeUpdate(DelegatingStatement.java:228)
at Lucene.Core.indexer.Action.doDelete(Action.java:184)
at Lucene.Core.indexer.Action.doGet(Action.java:48)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

does this proposal_id exist in all three of the tables: proposal, suitable_for, skill_need — hjpotter92
– hjpotter92, Commented Jul 6, 2012 at 12:33

TimonWang · Accepted Answer · 2012-07-06 12:36:05Z

1

Delete from can delete data from table like this but i don't know whether if can delete data like you post.

"DELETE  FROM proposal WHERE    proposal_id="+id
"DELETE  FROM suitable_fo WHERE    proposal_id="+id
"DELETE  FROM skill_need WHERE    proposal_id="+id

And before you invoke this, make sure param id is being checked to avoid sql injection.

answered Jul 6, 2012 at 12:36

TimonWang

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2 Comments

solidfox Over a year ago

what is the professional way for checking param before using it inside query due to avoiding mysql injection.

TimonWang Over a year ago

Thats not so easy, to your situation if id is integer. Make sure is integer before you execute the sql.

LSerni · Accepted Answer · 2012-07-06 12:41:21Z

0

Have you tried deleting from the three tables separately (possibly inside a transaction?)

Delete from multiple tables requires a table reference (e.g. a JOIN). It was born to delete linked records.

So you should try

 DELETE FROM proposal, suitable_for, skill_need
 FROM proposal JOIN suitable_for ON (proposal.proposal.id = suitable_for.proposal_id)
 JOIN skill_need ON (skill_need.proposal.id = proposal.proposal.id)
 WHERE proposal.proposal_id = ...

edited Jul 6, 2012 at 12:41

answered Jul 6, 2012 at 12:33

LSerni

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Comments

Jacob · Accepted Answer · 2012-07-06 12:43:00Z

0

Try using executeQuery instead of executeUpdate.

answered Jul 6, 2012 at 12:43

Jacob

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Comments

SirBif · Accepted Answer · 2012-07-06 12:52:47Z

0

I don't have a mySql db to test it, but I think the problem might be that it cannot determine which proposal_id it should use (having 3 tables). have you tried expliciting the join and specifying a table name before proposal_id?

something like "DELETE FROM proposal, suitable_for,skill_need WHERE proposal.proposal_id= suitable_for.proposal.proposal_id AND proposal.proposal_id=skill_need.proposal_id and proposal.proposal_id="+id

still, I agree with the others, 3 separate delete would be a better option..

answered Jul 6, 2012 at 12:52

SirBif

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