Databases
StackOverflow2013
Postsdbo
POMerge two tables with same column names, add counters
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POMerge two tables with same column names, add counters
    primarykey
    data
    text
    <p>I have two tables with the same columns, the first column is the name and the second is a count. I would like to merge these tables, so that each name appears with the added count of the two tables:</p> <pre><code>Table1: Table2: Result Table: NAME COUNT NAME COUNT NAME COUNT name1 1 name3 3 name1 1 name2 2 name4 4 name2 2 name3 3 name5 5 name3 6 name4 4 name6 6 name4 8 name5 5 name6 6 </code></pre> <p>As of the moment I have created a pretty ugly structure to execute this, and would like to know if it is possible to get the results in a more elegant way.</p> <p>What I have so far (Table1 is test1 and Table2 is test2):</p> <pre><code>create table test1 ( name varchar(40), count integer); create table test2 ( name varchar(40), count integer); create table test3 ( name varchar(40), count integer); create table test4 ( name varchar(40), count integer); create table test5 ( name varchar(40), count integer); insert into test4 (name, count) select * from test1; insert into test4 (name, count) select * from test2; insert into test3 (name , count) select t1.name, t1.count + t2.count from test1 t1 inner join test2 t2 on t1.name = t2.name; select merge_db(name, count) from test3; insert into test5 (name, count) (select name, max(count) from test4 group by name); CREATE FUNCTION merge_db(key varchar(40), data integer) RETURNS VOID AS $$ -- souce: http://stackoverflow.com/questions/1109061/insert-on-duplicate-update-postgresql BEGIN LOOP -- first try to update the key UPDATE test4 SET count = data WHERE name = key; IF found THEN RETURN; END IF;-- not there, so try to insert the key -- if someone else inserts the same key concurrently, -- we could get a unique-key failure BEGIN INSERT INTO test4(name,count) VALUES (key, data); RETURN; EXCEPTION WHEN unique_violation THEN-- do nothing, and loop to try the UPDATE again END; END LOOP; END; $$ LANGUAGE plpgsql; </code></pre>
    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. USevgeni
    plurals
    1. PL
      singulars
      1. LTLinked
    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
    1. VO
      singulars
      1. POMerge two tables with same column names, add counters
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POMerge two tables with same column names, add counters
      1. USdeinocheirus
      1. VTFavorite
    3. VO
      singulars
      1. POMerge two tables with same column names, add counters
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

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