mysql - MySQL 中的 SELECT 和 INSERT 语句的条件

Question

我想SELECT在条件等于 1 时做语句，这样就会执行INSERT语句，否则，它不会做任何事情。我认为您可以在我的代码中看到下面的内容。

SET @var = 1;

SELECT IF(@var = 1, 
    INSERT INTO tabulka VALUES('value1','name1'),
    0
)

谢谢

Answer 1

您只需要一个 IF 语句，而不是一个 SELECT。

if
    @var = 1
then
    insert into tabulka values('value1', 'name1');
end if

Answer 2

知道了！

http://sqlfiddle.com/#!2/66b33/1/0

create table test (
    int_field int, 
    str_field varchar(10) 
  );


set @var := 1;

insert into test 
   select  int_field, str_field 
   from    (select @var as int_field,
                   concat('var=',@var) as str_field 
           ) as temp
   where   @var=3;


set @var := 3;

insert into test 
   select  int_field, str_field 
   from    (select @var as int_field,
                   concat('var=',@var) as str_field 
           ) as temp
   where   @var=3; 


select * from test; 

结果是：

int_field      str_field
3              var=3