mysql - 如何在mysql语句中插入三元运算符

Question

我有一个查询，在 where 语句中我想插入一个三元运算符，如下所示:

WHERE 

 $self->is_defined? 'some_column = $self->defined' : 'some_other_column = $self->defined_some'
 AND blah blah blah
 AND blah blah blah

类似这样的事情。怎么做？

到目前为止，我的代码是这样的，它不起作用:

"SELECT blah blah blah

    WHERE 
     "$self->is_defined ? 'o.project_id = "$self->project_id"' : 'o.brand_id = "$self->brand_id"'"

Answer 1

首先，方法调用不会在双引号内插入，更不用说在单引号内插入。

创建sql时应该使用占位符以避免sql injection ,

my $sql = "SELECT * from ... WHERE ";

my ($cond, $val) = $self->is_defined 
  ? ("some_column = ?", $self->defined)
  : ("some_other_column = ?", $self->defined_some);

# constructing final sql..
$sql .= $cond;

my $st = $db_handle->prepare($sql) or die $db_handle->errstr;
$st->execute($val) or die $st->errstr;