sqlNode用法

1 动态SQL

传统的使用JDBC的方法，相信大家在组合复杂的的SQL语句的时候，需要去拼接，稍不注意哪怕少了个空格，都会导致错误。Mybatis的动态SQL功能正是为了解决这种问题， 其通过 if, choose, when, otherwise, trim, where, set, foreach标签，可组合成非常灵活的SQL语句，从而提高开发人员的效率

• if sqlNode

    select * from user where 
        deleteFlag = 0
        
               AND id=#{id}
        
  

• where SqlNode

    select * from user 
        
            
                id=#{id}
            
        

• trim sqlNode

    select * from user 

       
            
              AND  id=#{id}
            
      

• set SqlNode

    update user
    
       
            name = #{name}, 
            password = #{password}, 
            age = #{age}, 
      
    
        
            
                id = #{id}
            
            and deleteFlag = 0;
        

• foreach sqlNode

    SELECT *
    FROM POST P
    WHERE ID in
    
        #{item}
    

• choose sqlNode

    SELECT * FROM BLOG WHERE state = ‘ACTIVE’
    
        
            AND title like #{title}
        
        
            AND author_name like #{author.name}
        
        
            AND featured = 1