Mybatis中动态Sql语句的拼接分析

一、动态查询
1、方式一：

	
    
    
        select * from accounts where 1=1
        
            and number = #{number}
        
        
            and aid = #{aid}
        
    

2、方式二：

    
        select * from accounts
        
            
                and number = #{number}
            
            
                and aid = #{aid}
            
        
    

3、方式三：

	
        select * from accounts
        
            
                
                    and number = #{number}
                
                
                    and balance = #{balance}
                
                
                    and 1=2
                
            
        
    

二、动态插入

    
        insert into accounts(aid,
        
            number,
        
        balance) values (#{aid},
        
            #{number},
        
        #{balance})
    

三、动态更新

    
        update accounts set
        
            number = #{number},
        
        
            balance = #{balance},
        
        aid = #{aid} where aid = #{aid};
        /*关键在于此处是以aid为目标进行更新，再次更新aid，类似于where 1=1的sql拼接作用*/
    

四、数组、集合查询

	
    
        
            #{aid}