在idea连接完成数据库之后，在java源程序中使用sql语句如果显示SQLException,可能是
mysql-connector-java.jar文件在项目中不存在，只需将这个文件导入即可，
选择项目结构
选择模块里面的依赖 +号导入jre
选择mysql-connector-java.jar文件点击确定即可
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeQuery(ClientPreparedStatement.java:1003)
at com.itheima.test.queryData(test.java:50)
at com.itheima.test.main(test.java:36)
java.sql.SQLSyntaxErrorException: Table 'mydata.table_name' doesn't exist
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1092)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1040)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1348)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1025)
at com.itheima.test.addData(test.java:73)
at com.itheima.test.main(test.java:37)
java.sql.SQLSyntaxErrorException: Table 'mydata.table_name' doesn't exist
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1092)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1040)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1348)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1025)
at com.itheima.test.updateData(test.java:83)
at com.itheima.test.main(test.java:38)
java.sql.SQLSyntaxErrorException: Table 'mydata.table_name' doesn't exist
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.StatementImpl.executeUpdateInternal(StatementImpl.java:1333)
at com.mysql.cj.jdbc.StatementImpl.executeLargeUpdate(StatementImpl.java:2106)
at com.mysql.cj.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1243)
at com.itheima.test.deleteData(test.java:94)
at com.itheima.test.main(test.java:39)
