Re: Select from multiple tables
| From: | Kranthi Krishna | Date: | Thu, 01 Mar 2012 04:15:34 +0000 |
| Subject: | Re: Select from multiple tables | ||
| References: | 1 2 3 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-48208@lists.php.net to get a copy of this message | ||
Hi,
The examples I saw were regarding cartesian join not inner join. I
will read about inner joins. Also, the example i mentioned seems to be
a mistake. Both school and type will not be similar at the same time
Kranthi.
http://goo.gl/e6t3
On 1 March 2012 09:26, Kranthi Krishna <kranthi117@gmail.com> wrote:
> Hi,
>
> Thanks for the input. I have seen some tutorials on joins, they all
> suggest that MySql returns multiple rows
>
> For example
> --------------------------
> School | Board 1
> --------------------------
> School | Board 1
> -------------------------
>
> Now if I have another one-to-many relation
>
> -----------------------------------
> School | Board 1 | Type 1
> -----------------------------------
> School | Board 1 | Type 2
> -----------------------------------
> School | Board 2 | Type 1
> -----------------------------------
> School | Board 2 | Type 2
> ------------------------------------
>
> Using UNIQUE or something similar (like php.net/array_search ) causes
> problems when Type 1 = Type 2 etc.
>
> Kranthi.
> http://goo.gl/e6t3
>
>
>
> On 29 February 2012 19:43, Michael Stowe <mikegstowe@gmail.com> wrote:
>> Select table1.item1, table2.item1 from table1 inner join table2 on table1.key =
>> table2.foreignKey Where...
>>
>> You can also utilize left and right join to get data if there isn't a direct match (ie
>> customer may not have ordered anything so you want to do a left join on orders as there may not be
>> any order data but you still want to get the customer info).
>>
>> Hope that helps,
>> Mike
>>
>>
>>
>> Sent from my iPhone
>>
>> On Feb 29, 2012, at 8:01 AM, Kranthi Krishna <kranthi117@gmail.com> wrote:
>>
>>> Hi all,
>>>
>>> Say I have an object like
>>>
>>> array
>>> schoolName => string
>>> board => array
>>> string
>>> string
>>>
>>> I generally create two MySql tables
>>>
>>> schools: id PRIMARY KEY, SchoolName
>>> boards: id FOREGIN KEY refers Table A(id), board
>>>
>>> and then do two selects. The problem is that, the number of selects
>>> increase as the number of one-to-many relationships increase.
>>>
>>> Is there a better way to do this ? I have to extend an existing code
>>> so I cannot use any libraries like doctrine
>>>
>>> Kranthi.
>>> http://goo.gl/e6t3
>>>
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