Unknown column ‘drug_name‘ in ‘field list‘

报错信息：在使用了mybatis-plus框架查询时报错

com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'drug_name' in 'field list'
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_201]
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_201]
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_201]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_201]
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:406) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.Util.getInstance(Util.java:381) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1030) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3491) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3423) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1936) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2060) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2542) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1734) ~[mysql-connector-java-5.1.6.jar:na]
	at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:995) ~[mysql-connector-java-5.1.6.jar:na]
	at com.zaxxer.hikari.pool.ProxyPreparedStatement.execute(ProxyPreparedStatement.java:44) ~[HikariCP-3.4.5.jar:na]
	at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.execute(HikariProxyPreparedStatement.java) ~[HikariCP-3.4.5.jar:na]
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79) ~[mybatis-3.5.6.jar:3.5.6]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_201]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_201]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_201]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_201]
	at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:63) ~[mybatis-3.5.6.jar:3.5.6]
	at com.sun.proxy.$Proxy73.query(Unknown Source) ~[na:na]
	at com.baomidou.mybatisplus.core.executor.MybatisSimpleExecutor.doQuery(MybatisSimpleExecutor.java:69) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:325) ~[mybatis-3.5.6.jar:3.5.6]
	at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) ~[mybatis-3.5.6.jar:3.5.6]
	at com.baomidou.mybatisplus.core.executor.MybatisCachingExecutor.query(MybatisCachingExecutor.java:165) ~[mybatis-plus-core-3.4.1.jar:3.4.1]
	at com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor.intercept(MybatisPlusInterceptor.java:65) ~[mybatis-plus-extension-3.4.1.jar:3.4.1]

报错原因：没有找到对应的数据库中的对应的表字段

解决方案：加注解 @TableField(“drugName”) // 属性为数据库表字段，因为mybatis-plus默认数据库字段区分组合词，区分大小写，如果不想加注解可以使用drugname这种方式，不加大写字母

package com.fh.model;

import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.boot.jackson.JsonComponent;
import org.springframework.format.annotation.DateTimeFormat;

import java.util.Date;

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("d_drug")  // 说明数据库表名
public class Drug  {
    
    
    private Integer id;
    @TableField("drugName")  // 说明数据库字段名
    private String drugName;
    @TableField("drugPrice")
    private Integer drugPrice;//价格
    @TableField("drugSales")
    private Integer drugSales;//销量
    @TableField("drugStock")
    private Integer drugStock;//库存
    @TableField("isOTC")
    private Integer isOTC;//1是非处方药 2是处方药
    private String person;//适合人群(1幼儿 2少年 3青年 4中年 5老年 6孕妇)
    @DateTimeFormat(pattern = "yyyy-MM-dd")
    @JsonFormat(pattern = "yyyy-MM-dd",timezone = "GMT+8")
    @TableField("producedDate")
    private Date producedDate;
    private String photo;
        @TableField("brandId")
    private Integer brandId;
    @TableField(exist = false)   // 数据库表中没有这个字段,但又必须使用，外键名称,两表联查使用
    private String brandName;
    @TableField("areaId")
    private Integer areaId;
    @TableField(exist = false)  // 数据库表中没有这个字段,但又必须使用，外键名称,两表联查使用
    private String areaName;
}