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【MySQL函数】MYSQL IFNULL和IF函数的使用

 

下文对MYSQL IFNULL函数的使用进行了详细的叙述,供您参考学习,如果您在MYSQL IFNULL函数使用方面遇到过类似的问题,不妨一看。

 

MYSQL IFNULL(expr1,expr2)     
     

如果expr1不是NULL,IFNULL()返回expr1,否则它返回expr2。IFNULL()返回一个数字或字符串值,取决于它被使用的上下文环境。          

mysql> select IFNULL(1,0);                           -> 1      mysql> select IFNULL(0,10);                           -> 0      mysql> select IFNULL(1/0,10);                           -> 10      mysql> select IFNULL(1/0,'yes');                           -> 'yes '    

 

   

【MySQL函数】MYSQL IFNULL和IF函数的使用_MySQL

 

 

 

IF(expr1,expr2,expr3)          

如果expr1是TRUE(expr10且expr1NULL),那么IF()返回expr2,否则它返回expr3。IF()返回一个数字或字符串值,取决于它被使用的上下文。          

mysql> select IF(1>2,2,3);                           -> 3      mysql> select IF(1<2,&#39;yes&#39;,&#39;no&#39;);                           -> yes     mysql> select IF(strcmp(&#39;test&#39;,&#39;test1&#39;),&#39;yes&#39;,&#39;no&#39;);   //strcmp(&#39;test&#39;,&#39;test1&#39;)=-1                        -> yes     

 

     

     【MySQL函数】MYSQL IFNULL和IF函数的使用_MySQL

     

 

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