how to remove repetition of data in mysql? - php

This is my detail table:
This is my contact table:
Here are two rows in details table and 4 rows (each details have 2) in contact table. When I use join query I get 4 results row but I want only 2 row(one row of details row with one contact of that corresponding details).
my query:
$this->db->select('*');
$this->db->from('dots_center_detail');
$this->db->join('dots_center_contact', 'dots_center_contact.registration_id = dots_center_detail.registration_id','left');

try this
$this->db->query("
SELECT DISTINCT dots_center_detail.registration_id, dots_center_contact.contact
FROM dots_center_detail
LEFT JOIN dots_center_contact ON dots_center_contact.registration_id = dots_center_detail.registration_id
")

Using select('DISTINCT *') in place of select('*') may give the result you need. It's worth a try.
Or you can create a view like this to go with your table definitions.
CREATE OR REPLACE VIEW dots_center_unique_contact AS
SELECT DISTINCT * FROM dots_center_contact;
Then refer to that dots_center_unique_contact view in your join operation.
Your best bet long term is to figure out why you have duplicate rows, and tighten up your business rules so you don't.

Related

Query selected columns from two tables with a Condition clause

I have two tables-
1) ****Company_Form****
[Contract_No#,Software_Name,Company_Name,Vendor_Code]
2) ****User_Form****
[Contract_No,Invoice_No#,Invoice_Date,Invoice_Amount,Invoice_Submit_Date]
Fields denoted with # and bold are primary keys.
=>The user has to enter a software name for which he wants to get the data of.
=>I have to structure a query in which I have to display the result in the following form:
[Contract#,Software_Name,Company_Name,Invoice_No,Invoice_Date,Invoice_Submission_Date]
Now,
one Contract_No can contain many Invoice_no under its name in
the User Form table.
One Contract_No can occur one time only in
Company_Form table
The retrieved records have to be group by the latest Invoice_Date
I came to the logic that:
I have to first retrieve all the contract numbers with that software
name from Company_Form table.
I have to query that contract number from User_Form table and display
the data for each matched contract no. fetched from Company_Form
table.
The problem is that I am unable to structure a query in SQL that can do the task for me.
Kindly help me in formulating the query.
[PS] I am using SQL with PHP.
I tried a query like:
I tried one approach as :
SELECT a.ContractNo,a.SoftwareName,a.CompanyName,b.InvoiceNo,b.InvoiceDate,b.InvAmount,b.InvoiceSubmitDate
FROM Company_Form as a,User_Form as b
WHERE b.ContractNo IN(SELECT ContractNo FROM Company_Form WHERE
SoftwareName='$Sname') AND a.ContractNo=b.ContractNo;
But I am getting a error that sub query returns more than 1 row.
Can I get help from this?
I am assuming you are attempting to find the most recent price of the user selected software and its corresponding invoice. Here is an approach to do this. If this is tested to your satisfaction, I can add necessary explanation.
select uf.Contract_No#,
cf.Software_Name,
cf.Company_Name,
uf.Invoice_No#,
uf.Invoice_Date,
uf.Invoice_Amount,
uf.Invoice_Submit_Date
from User_Form uf
inner join (
-- Most recent sale of software
select Contract_No#, max(Invoice_Date)
from User_Form
group by Contract_No#
) latest
on (
-- Filter via join for latest match records
uf.Contract_No# = latest.Contract_No#
and uf.Invoice_Date = latest.Invoice_Date
)
inner join Company_Form cf
on cf.Contract_No# = uf.Contract_No#
where cf.Software_name = :software_name
If the requirement allows your sub query to return more than one row, I would suggest you to use IN instead of = in the where clause of your main query.
Please note that I have just looked at the query and have not fully understood the requirements.
Thanks.
I worked around for some time and finally came to the following query which works like a charm
SELECT a.ContractNo,a.SoftwareName,a.CompanyName,b.InvoiceNo,b.InvoiceDate,b.InvAmount,b.ISD
FROM Company_Form as a,User_Form as b
WHERE b.ContractNo IN (SELECT ContractNo FROM Company_Form WHERE SoftwareName='$Sname')
AND a.ContractNo=b.ContractNo;
If anybody needs help in understanding the logic of this query,feel free to comment below.

How do i get record by id in php

Here is my database view
I need to get title by using student id 232. But student id is stored in array like 192,229,232. How can i retrive 232 records only?
Please guide me..
Thanks
you use IN clause for get record from array
<?php
$sql = 'SELECT *
FROM `table`
WHERE `id` IN (' . implode(',', array_map('232', $array)) . ')';
Use FIND_IN_SET
Eg.
SELECT * FROM event WHERE FIND_IN_SET(232,student);
You can use LIKE condition to fetch results that contain this student id:
SELECT * FROM `event` WHERE student LIKE '%232%';
This will return you all rows that contain '232' in student column.
But if you have an opportunity to change your table structure I would suggest you to extract student column to a pivot table.
You could create event_student table that would contain just two columns: event and student. And each row would link particular student to a particular event. The data could be easily extracted with a simple JOIN:
SELECT * FROM `event` e
INNER JOIN `event_student` es ON e.eventID=es.event
WHERE es.student=232;
If you store connections between student and events this way you will gain flexibility in your queries and avoid possible mistakes that may occur when using the answer suggested above. Imagine that you have a student with id 2324 or 12323. Both of them contain desired '232' string and both will match the '%232%' pattern and lead to returning you wrong data.

SQL Query result, comparison and where clause

I am building a site and i need to retrieve some information. I have this query.
$SQL = "SELECT distretto_108, provinca_113, regioni_116, tipologia_pdv_106,
richiesta_ccnl_107, coop_va_109, nome_pdv_110,
indirizzo_pdv_111, localita_112
FROM civicrm_value_informazioni_su_tute_le_schede_p_22 ";
I need to add this other code:
WHERE civicrm_event.title_en_US='".addslashes($_GET["titles"])."'
but it's not working...
i need to compare let's say the id of another table with the id of the current table... How to do that?
Thanks in advance...
You should learn something about joining tables...
Do not know what the relation is between the two tables (simply said: what column from one table is pointing to what column at other one), but try something similar (modification needed to meet You DB structure) - now lets assume both tables have related column called event_id:
$SQL = "SELECT distretto_108, provinca_113, regioni_116, tipologia_pdv_106,
richiesta_ccnl_107, coop_va_109, nome_pdv_110,
indirizzo_pdv_111, localita_112
FROM civicrm_value_informazioni_su_tute_le_schede_p_22 cvistlsp22
LEFT JOIN civicrm_event ce ON ce.event_id = cvistlsp22.event_id
WHERE ce.title_en_US='".mysql_real_escape_string($_GET["titles"])."'";
civicrm_value_informazioni_su_tute_le_schede_p_22 table name is very long and You will not be able to create a table with such long name in other DBMS (e.g. ORACLE), so try to make it shorter while still self-describing...
If You want to join tables they have to have a relation, read more about relations and how to use them here: http://net.tutsplus.com/tutorials/databases/sql-for-beginners-part-3-database-relationships/
You are retrieving the data from table civicrm_value_informazioni_su_tute_le_schede_p_22 in your query while the where clause you are adding, refers to the table civicrm_event. You need to add this new table in the from clause and do a join among the two tables using some common key. Example below:
$SQL = "
SELECT distretto_108, provinca_113, regioni_116, tipologia_pdv_106, richiesta_ccnl_107, coop_va_109, nome_pdv_110, indirizzo_pdv_111, localita_112
FROM civicrm_value_informazioni_su_tute_le_schede_p_22
JOIN civicrm_event ON civicrm_value_informazioni_su_tute_le_schede_p_22.ID_PK = civicrm_event.ID_FK
WHERE civicrm_event.title_en_US='".addslashes($_GET["titles"])
";
You need to replace the ID_PK and ID_FK with the relevant Primary and Foreign Keys that bind the tables together.
Please note using query params like that is not recommended. Please read PHP Documentation here for more explanation.

How to create MYSQL record source for two related tables

I currently have a page that displays player information from one table named "tblplayers". The query I am currently using is:
$result = mysql_query("SELECT * FROM tblPlayers WHERE lng_RecordID_PK = '".$playerid."' ");
I have a second table named "tblMatches" containing match results for the players. I want the recordset to include the rows from "tblMatches" WHERE "P1_ID" OR "P2_ID" is equal to the "lng_RecordID_PK" field from "tblPlayers".
How can I revise my $result query so that it returns:
one row from tblPlayers
multiple rows from tblMatches
???
Thanks for helping me out.
That's called a 'join':
SELECT tblPlayers.*, tblMatches.*
FROM tblPlayers
LEFT JOIN tblMatches ON Ing_RecordID_PK IN (P1_ID, P2_ID)
You are asking about joining two tables where the second table potentially has multiple records for each one in the first table. This is a one-to-many or 1:N join, and most often done using a LEFT JOIN meaning you want everything in the "left" table, and all the records that match from the "right" table, and that you may have some records on the "left" side with no matches.
Your query would look like this:
SELECT *
FROM tblPlayers
LEFT JOIN tblMatches
ON (tblPlayers.lng_RecordID_PK = tblMatches.P1_ID
OR tblPlayers.lng_RecordID_PK = tblMatches.P2_ID)
WHERE tblPlayers.lng_RecordID_PK = #PlayerID;
Bits of advice:
Avoid selecting all columns (*) and instead select just those that you need for the query.
Consider using parameterized queries to avoid SQL injection attacks. If your variable were to be submitted or altered maliciously, it could result in compromised data or security. (See PHP Data Objects for example.)
There is no way to get rows from two different tables in the way you are describing. You could not get a row from one table, and two rows from another one. What you could is do two separate queries, or use a JOIN statement to join the two tables together, and then receive results from the resulting joined table. If you provide more information about your table structure I am sure more help can be given.

select from multiple table with mysql

I had my query set up the other day as so
$query = "SELECT card_id,title,description,meta_description,seo_keywords,price
FROM cards,card_cheapest order by card_id";
As you can see, I was selecting card_id,title,description,meta_description,seo_keywords from the table cards, and price was coming from cheapest_card. They both have the card_id in common (in both tables). However, I ran into a bit of an issue. When I run the query in navicat lite, I receive an error "card_id is ambiguous". Was I doing something wrong?
When 2 or more tables have a column that is named the same, you have to qualify the table you want the column to be from.
i.e.:
$query = "SELECT cards.card_id,title,description,meta_description,seo_keywords,price
FROM cards,card_cheapest order by card_id";
Furthermore, do you really want to run the query this way, without a WHERE/JOIN-clause to define how to JOIN the two tables?
$query = "SELECT cards.card_id,title,description,meta_description,seo_keywords,price
FROM cards,card_cheapest WHERE cards.card_id = card_cheapest.card_id
ORDER BY card_id";
When you have the same column name in two tables you're selecting from, you have to prefix the part in the SELECT with one of the table names (it doesn't matter which if it's the same data)
such as SELECT cards.card_id, ...
EDIT: However, cularis's answer is much more explanatory than mine, and take note about joining the two card_id columns if you want to get correct results.
When you run queries that get information from multiple tables with shared field names you need to specify from which table you want to extract what field. You do this by specifying the table name before the field name.
In your case you have two options:
cards.card_id or card_cheapest.card_id.
Also I agree with #cularis, you are probably better of doing a join, but still you will need to specify which card_id you want to select: the one from cards or card_cheapest.

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