Databases
StackOverflow2013
Postsdbo
POHow to combine data from multiple tables using SQL?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to combine data from multiple tables using SQL?
    primarykey
    data
    text
    <p>I have following tables in my MySql database :</p> <pre><code>+----------------------------------------------+ PROJECT +----------------------------------------------| +----------------------------------------------| project_id | team_size | from_date +----------------------------------------------| 1 | 34 | 1 Dec 2010 +----------------------------------------------| 2 | 2 | 2 Jan 1902 +----------------------------------------------| 3 | 99 | 15 Aug 1947 +----------------------------------------------+ </code></pre> <hr> <pre><code>+----------------------------------------------+ Technologies +----------------------------------------------+ +----------------------------------------------+ technology_id | technology_name +----------------------------------------------+ 1 | Java +----------------------------------------------+ 2 | CPP +----------------------------------------------+ 3 | Hibernate +----------------------------------------------+ 4 | EJB +----------------------------------------------+ 5 | Python +----------------------------------------------+ 6 | Hadoop +----------------------------------------------+ 7424 | Perl +----------------------------------------------+ </code></pre> <hr> <p>To link <code>Project</code> and <code>Technologies</code> tables I have following table : </p> <pre><code>+----------------------------------------------+ Project_Technologies +----------------------------------------------+ +----------------------------------------------+ Project_ID | Technology_ID +----------------------------------------------+ 1 | 2 +----------------------------------------------+ 1 | 7424 +----------------------------------------------+ 2 | 1 +----------------------------------------------+ 2 | 3 +----------------------------------------------+ 2 | 4 +----------------------------------------------+ 2 | 5 +----------------------------------------------+ </code></pre> <p>I want to show data in one table in the form of rows and columns in UI. For example : </p> <pre><code>+---------------------------------------------------+ project_id | team_size | from_date | technologies |---------------------------------------------------| | 1 | 34 | 1 Dec 2010| CPP, Perl | |---------------------------------------------------| | 2 | 2 | 2 Jan 1902| Java, Hibernate, EJB, Python | |---------------------------------------------------| | 3 | 99 |15 Aug 1947| | +---------------------------------------------------+ </code></pre> <p>I am not able to form sql query to get something like this. I have tried following query which is giving me duplicate rows.</p> <pre><code>select pr.project_id,pr.team_size,pr.from_date,tech.technology_name from project pr, project_technologies ptech, technologies tl where pr.project_id=ptech.project_id and ptech.technology_id=tl.technology_id </code></pre> <p>I would like to know how to avoid duplicate rows? Currently this query is giving me 2 rows when project_id=1 and 4 rows when project_id=2</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USShekhar
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to combine data from multiple tables using SQL?
      1. This table or related slice is empty.
      1. VTUpMod
    1. CODid you try using DISTINCT ?
      singulars
      1. POHow to combine data from multiple tables using SQL?
      1. USSandeep Pathak
    2. CO@CodeBuzz, ya just now I tried distinct but I am getting same output. I'll add output of current query in question.
      singulars
      1. POHow to combine data from multiple tables using SQL?
      1. USShekhar
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload