MySQL/Mybatis多个AND和OR混用注意事项

mysql中AND的优先级高于OR，所以在查询时，会优先执行AND条件，除非使用（）来将一个AND和OR括起来，这样才能使得OR得以按照语句的顺序执行。

如下图所示：

java测试代码

@Test
    public void TestMutil(){
        Species species = new Species();
        ArrayList arrayList = new ArrayList();
        arrayList.add("长喙蚤");
        arrayList.add("尤氏");
        List querySpeciesesListByMutilCondition = this.speciesMapper.querySpeciesesListByMutilCondition(arrayList, species.getEnglishName(), species.getHost(), species.getPosition(), species.getLocation(), species.getPhylum(), species.getClassName(), species.getOrder(), species.getFamily(), species.getJenus());
        
        for (Species s : querySpeciesesListByMutilCondition) {
            System.out.println(s);
        }
        System.out.println(querySpeciesesListByMutilCondition.size());
        
    }

Mapper文件中没有使用（）放在语句中执行情况

		SELECT * FROM t_json_species
		
			AND englishName like CONCAT('%',#{englishName},'%') OR sameName like CONCAT('%',#{englishName},'%')
			AND host like CONCAT('%',#{host},'%')
			AND position like CONCAT('%',#{position},'%')
			AND location like CONCAT('%',#{location},'%')
			AND phylumName = #{phylumName}
			AND className = #{className}
			AND orderName = #{orderName}
			AND familyName = #{familyName}
			AND jenusName = #{jenusName}
			
				AND name like CONCAT('%',#{name},'%') OR sameName like CONCAT('%',#{name},'%')
			
		
		
	

Mapper文件中使用（）放在语句中执行情况

		SELECT * FROM t_json_species
		
			AND englishName like CONCAT('%',#{englishName},'%') OR sameName like CONCAT('%',#{englishName},'%')
			AND host like CONCAT('%',#{host},'%')
			AND position like CONCAT('%',#{position},'%')
			AND location like CONCAT('%',#{location},'%')
			AND phylumName = #{phylumName}
			AND className = #{className}
			AND orderName = #{orderName}
			AND familyName = #{familyName}
			AND jenusName = #{jenusName}
			
				AND (name like CONCAT('%',#{name},'%') OR sameName like CONCAT('%',#{name},'%'))
			
		
		
	

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补充：

如果这里使用多个%来解决上述的含有多个OR和AND情况，那么所实现功能会有问题，因为多个关键词有%来连接，会有一个次序问题。具体效果见下图