Java 选择语句中带有参数化 where 子句的 PreparedStatement 抛出异常
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PreparedStatement with parameterised where clause in select statement throwing Exception
提问by SME
I am getting exception as SQLException showing there is a something wrong in the syntax and check the manual for same.
我收到异常，因为 SQLException 显示语法有问题，并检查手册是否相同。
My java code is as follows.
我的java代码如下。
PreparedStatement pst;
String sql ="SELECT * FROM patient.medicine where _id=?";
pst = cn.prepareStatement(sql);
pst.setInt(1, 1);
ResultSet rs = pst.executeQuery(sql);
If I execute this by appending the variable holding a value for id, everything works fine.
如果我通过附加包含 id 值的变量来执行此操作，则一切正常。
*SELECT * FROM patient.medicine where _name=?*
Oct 19, 2013 11:15:46 AM com.seed.entity.Patient getData
SEVERE: null
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 '?' at line 1
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.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:1053)
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:2728)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2678)
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1612)
at com.seed.entity.Patient.getData(Patient.java:257)
at com.seed.entity.Patient.main(Patient.java:360)
采纳答案by Paul Vargas
There is one error in you code:
您的代码中有一个错误：
PreparedStatement pst;
String sql ="SELECT * FROM patient.patient P WHERE P._ID = ?";
pst = cn.prepareStatement(sql);
pst.setInt(1, 1);
ResultSet rs = pst.executeQuery(); // without arguments
回答by Ravi Thapliyal
Your SQL should just be
你的 SQL 应该只是
SELECT * FROM patient WHERE patient._ID = ?
The table name patient.patientseems incorrect since the column is referred to as patient._ID
表名patient.patient似乎不正确，因为该列被称为patient._ID
回答by SpringLearner
change this String sql = "SELECT * FROM patient.patient WHERE patient._ID=?";
改变这个 String sql = "SELECT * FROM patient.patient WHERE patient._ID=?";
to String sql = "SELECT * FROM patient WHERE patient._ID=?";
到 String sql = "SELECT * FROM patient WHERE patient._ID=?";
