Re: MySQL two tables and an uneven number of rows

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Thanks Bert,
Sorry for late response, but I had to step away from this for a moment to work on other things.
Will most likely be back though as things are not working still.

Thank you for your responses.

Best,

Karl DeSaulniers
Design Drumm
http://designdrumm.com




> On Sep 13, 2016, at 2:15 AM, B. Aerts <ba_aerts@xxxxxxxxx> wrote:
> 
> On 13/09/16 08:42, Karl DeSaulniers wrote:
>>> On Sep 12, 2016, at 2:53 PM, B. Aerts <ba_aerts@xxxxxxxxx> wrote:
>>> 
>>> On 12/09/16 05:24, Karl DeSaulniers wrote:
>>>> Hello All,
>>>> Hoping you can help clear my head on this. I have two MySQL tables for custom fields data to be stored.
>>>> 
>>>> 	custom_fields			custom_fields_meta
>>>> 
>>>> custom_fields is the info for the actual field displayed in the html and custom_fields_meta is the data stored from entering a value on said field in the form.
>>>> 
>>>> Custom fields can be added and removed at will by the user and so when for instance, adding a field,
>>>> it currently creates an uneven number of rows in the custom_fields_meta if there were any entries with fields create prior to this new one.
>>>> 
>>>> Currently I have this code:
>>>> 
>>>> $SQL = "SELECT ft.*, mt.Meta_Value
>>>> 		FROM `CUSTOM_FIELDS` ft
>>>> 		LEFT JOIN `CUSTOM_FIELDS_META` mt
>>>> 		ON mt.Field_ID = ft.Field_ID
>>>> 		WHERE mt.Order_ID=%d
>>>> 		ORDER BY ft.Field_ID ASC";
>>>> 
>>>> I have tried JOIN, FULL JOIN, FULL OUTER JOIN, OUTER JOIN and LEFT JOIN.
>>>> If I manually put in the missing rows in the meta table, left join works.
>>>> However, manually updating prior entries is not going to happen.
>>>> 
>>>> So my question is how do I get all the table rows in both tables even if there is not a row to match on the meta table?
>>>> or
>>>> How would I update the prior entries to include this new field in the meta table and keep things orderly?
>>>> The meta is stored per order id and so there is groups of meta data per order id. I would like to avoid scattered data.
>>>> Is there a way to push the index down to fit them in or is this just going to be too costly on server resources?
>>>> 
>>>> TIA,
>>>> 
>>>> Best,
>>>> 
>>>> Karl DeSaulniers
>>>> Design Drumm
>>>> http://designdrumm.com <http://designdrumm.com/>
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>> Hi Karl,
>>> 
>>> I can't really follow your problem ... Any chance to post 2 dummy table layouts to show what you want, and what you get ?
>>> 
>>> And it isn't something you could solve with a UNION ?
>>> 
>>> 
>> 
>> 
>> Hello,
>> Thanks fro your reply. I can try. :)
>> 
>> BEFORE:
>> 
>> CUSTOM_FIELDS:
>> 
>> `Field_ID`, `Field_Group`, `Field_Label`, `Field_Name`, `Field_Slug`, `Field_Type`, `Field_Description`, `Field_Values`, `Field_Display`, `Field_Required`, `Field_Date_Created`
>> |————————————————————————————————————————————————————————————————————————————————|
>> (1, 'Pickup Info', 'Phone 1', 'Origin_Phone1', 'origin-phone1', 'phone', 'Pickup Main phone number', '', 'Yes', 'No', '2015-04-19 08:46:10'),
>> (2, 'Pickup Info', 'Phone 2', 'Origin_Phone2', 'origin-phone2', 'phone', 'Pickup alternate phone number 1', '', 'Yes', 'No', '2015-04-19 08:46:11'),
>> (3, 'Pickup Info', 'Phone 3', 'Origin_Phone3', 'origin-phone3', 'phone', 'Pickup alternate phone number 2', '', 'Yes', 'No', '2015-04-19 08:46:12')
>> 
>> CUSTOM_FIELDS_META:
>> 
>> `Meta_ID`, `Field_ID`, `Order_ID`, `Meta_Value`
>> |—————————————————————|
>> (1, 1, 1003, '555-123-4567'),
>> (2, 2, 1003, ''),
>> (3, 3, 1003, '')
>> 
>> 
>> Then lets say the user wants to add a cell phone field.
>> 
>> AFTER:
>> 
>> CUSTOM_FIELDS:
>> 
>> `Field_ID`, `Field_Group`, `Field_Label`, `Field_Name`, `Field_Slug`, `Field_Type`, `Field_Description`, `Field_Values`, `Field_Display`, `Field_Required`, `Field_Date_Created`
>> |————————————————————————————————————————————————————————————————————————————————|
>> (1, 'Pickup Info', 'Phone 1', 'Origin_Phone1', 'origin-phone1', 'phone', 'Pickup Main phone number', '', 'Yes', 'No', '2015-04-19 08:46:10'),
>> (2, 'Pickup Info', 'Phone 2', 'Origin_Phone2', 'origin-phone2', 'phone', 'Pickup alternate phone number 1', '', 'Yes', 'No', '2015-04-19 08:46:11'),
>> (3, 'Pickup Info', 'Phone 3', 'Origin_Phone3', 'origin-phone3', 'phone', 'Pickup alternate phone number 2', '', 'Yes', 'No', '2015-04-19 08:46:12'),
>> (4, 'Pickup Info', 'Cell', 'Origin_Cell', 'origin-cell', 'phone', 'Pickup cell phone number', '', 'Yes', 'No', '2015-04-19 08:46:13')
>> 
>> CUSTOM_FIELDS_META:
>> 
>> `Meta_ID`, `Field_ID`, `Order_ID`, `Meta_Value`
>> |—————————————————————|
>> (1, 1, 1003, '555-123-4567'),
>> (2, 2, 1003, ''),
>> (3, 3, 1003, '')
>> 
>> The 4th field id is not in the meta table. So when I read out what is in the custom fields and matching meta data, cell phone does not show up for order that were processed before adding the custom field cell phone. I am trying to show the cell phone field on old orders as well even if there is not a row representing data in the meta table.
>> 
>> Hope that clears it up and not mud it up.. :P
>> 
>> Best,
>> 
>> Karl DeSaulniers
>> Design Drumm
>> http://designdrumm.com
>> 
> 
> Hi Karl,
> 
> indeed this should work with a left JOIN. Did a quick test in SQLite, and got this to work (just to indicate that your principle is correct) :
> 
> sqlite> select * from table1 ;
> 1|100
> 2|200
> 4|400
> sqlite> select * from table2 ;
> 1|1000
> 2|2000
> 3|3000
> sqlite> select * from table1 join table2 on table1.ID = table2.ID ;
> 1|100|1|1000
> 2|200|2|2000
> sqlite> select * from table1 left join table2 on table1.ID = table2.ID ;
> 1|100|1|1000
> 2|200|2|2000
> 4|400||
> sqlite> select * from table1 right join table2 on table1.ID = table2.ID;
> Error: RIGHT and FULL OUTER JOINs are not currently supported
> 
> 
> I don't use MySQL (too advanced for my needs) - but a quick Google led me to this : http://dev.mysql.com/doc/refman/5.7/en/left-join-optimization.html
> The 7th bullet talks of a snag based on the NULL - NOT NULL attribute of columns. Could this create your problem ?
> 
> 
> If you simplify your query to the most basic form ( $SQL = "SELECT *
> 		FROM `CUSTOM_FIELDS` ft
> 		LEFT JOIN `CUSTOM_FIELDS_META` mt
> 		ON mt.Field_ID = ft.Field_ID;) , what does it yield ?
> 
> If you create 2 equally simple test tables with no additional attributes per column, what does it yield ?
> 
> If nothing else helps, and no better placed poster comes up with a solution, one way to solve this, is the following.
> Everytime a user creates a new custom field, basically what he does, is changing the "template" for an order or a form.
> Retro-actively adapt the template on all old orders using that template, with a default value.
> 
> 
> Hope this helps,
> 
> Bert
> 
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