如何在MySQL查询中使用mysql列内容作为php数组的索引（键）？

Question

I want to know how or if I can use the content of a column in mysql as a key (index) to a php array within the mysql query.

Example:

Column name: period

Column contents: (one of) 'Year','Month','Fortnight','Week','Hour','Day'

My php array:

$x = array(
'Year' => 1,
'Month' => 12,
'Fortnight' => 26,
'Week' => 52,
'Hour' => 1872,
'Day' => 365
);

Another variable $y can be any number (say < 1,000,000)

I want to write a WHERE (or HAVING) condition such as...

WHERE '$x[`period`]' * '$y' > 12345

Eg when the contents of period = 'Month', $y should be multiplied by 12 before being tested to be > 12345

What is the best (most efficient) way to do this, other than (say) a long CASE conditional?

Thank you

Answer 1

i have write demo query

<?php
$x = array(
'Year' => 1,
'Month' => 12,
'Fortnight' => 26,
'Week' => 52,
'Hour' => 1872,
'Day' => 365
);
$y=10;

$sql="select * from table where ".$x['Month']*$y." > 12345" ;

echo $sql;

in $x[] select your value to multiply

Answer 2

You can use case instead of php array:

<?php
$y = 100;

$sql = "select * from tablename
where (case `period`
  when 'Year' then 1
  when 'Month' then 12
  when 'Fortnight' then 26
  when 'Week' then 52
  when 'Hour' then 1872
  when 'Day' then 365
end) * {$y} > 12345";

Answer 3

Try this:

<?php
  $y = 10;
  $period = "Month";

  $x = array(
    'Year' => 1,
    'Month' => 12,
    'Fortnight' => 26,
    'Week' => 52,
    'Hour' => 1872,
    'Day' => 365
  );

  $sql="select * from table where ".($x[$period] * $y)." > 12345" ;

  echo $sql;