将一个表的ID与另一个表的user_id匹配以获取mysql中的记录

Question

I have two tables,lets say x and y. i am using two queries to fetch x table data by one query and fetch all rows from y table matching x's id with y's UserId

here is my mysql

include 'config.php';

$sql1= mysql_query("select FirstName,MiddleName,LastName,Gender,Location,Email,Mobile from personaldetails limit 1");

$sql2 = mysql_query("select BookTilte,BookGenre,BookWriter,BookDescription from bookdetails where personaldetails.Id = bookdetails.UserId ")

Please also suggest some alternative solution if it's wrong

Answer 1

you can use from INNER JOIN in these cases

SELECT FirstName,MiddleName,LastName,Gender,Location,Email,Mobile,BookTilte,BookGenre,BookWriter,BookDescription FROM `personaldetails` as `PD` INNER JOIN `bookdetails` AS `BD` ON `PD`.`Id` = `BD`.`UserId`

Note: mysql_query is deprecated and you should use mysqli functions

Answer 2

Try with below query

$sql1= mysql_query("select a.FirstName,a.MiddleName,a.LastName,a.Gender,a.Location,a.Email,a.Mobile,b.BookTilte,b.BookGenre,b.BookWriter,b.BookDescription from personaldetails as a join bookdetails as b on a.Id=b.UserId  limit 1");

Join will combine the two tables.

a and b are aliases of two tables. By using aliases, we can specify which field select from which table.

a.Id=b.UserId is for specify the primary key and reference key

Answer 3

It s not wrong, it could be the right thing to do sometimes.

An alternative solution could be

$str = <<<MARKER
SELECT FirstName,MiddleName,LastName,Gender,Location,Email,Mobile 
FROM personaldetails 
INNER JOIN bookdetails ON (personaldetails.Id = bookdetails.UserId)
ORDER BY personaldetails.Id
MARKER;
$sql1= mysql_query($query);

Notes,

• you don't need the limit anymore as it would return only the first row.

• For each bookdetails , you ll find a personaldetails line ( personaldetails will be duplicated),

• I added an ORDER BY clause to show you.

• you should reference primary keys, or indexed columns, or add new indexes