sql joins

[Escape_Artist]

teach me all joins.

[Pigeon]

You don't know anything about joins?

[Escape_Artist]

I'm brain dead after today.....


Inner joins = only those that match
Outer = all and nulls for the non match
left = everything from the first table in the join and matches/null
full outer = non matching

.........ugh my brain hurts to much at the moment to explain what I need... .. 1 sec

I want to combine both tables primary keys into one distinct list


Distinct_Primary_Key_All (from table 1 & 2), Table_1_variable, Table_2_variable

I think I just worked myself retarded... it seems simple since i typed it out.... i suck at sql.


I'm a lefty cause I always had one table with all the primary keys.

[Pigeon]

union maybe

[Pigeon]

select id from a
union
select id from b

would give the ids. if you add the extra column from each table, I believe they are distinct based on the combination of id and other colunm. That might not be what you want.

[Dr Exile]

Why don't you guys just use Fortran and simplify your live's?

[Royal]

Why don't you guys just use Fortran and simplify your live's?

ahahaha

I took a class in that. Taught by mathematician that solved some 100+ year old math problem.

[Pigeon]

SELECT a.id, a.f1, b.f1
FROM a
RIGHT OUTER JOIN b
ON a.id=b.id

Only if the ID exists in both tables

Code: Select all

mysql> select * from a;
+------+------+
| id   | f1   |
+------+------+
|    1 | a    |
|    2 | aa   |
+------+------+

mysql> select * from b;
+------+------+
| id   | f1   |
+------+------+
|    1 | b    |
|    2 | bb   |
+------+------+

+------+------+------+
| id   | f1     | f1   |
+------+------+------+
|    1 | a    | b    |
|    2 | aa   | bb   |
+------+------+------+

Add an id only to b

+------+------+
| id   | f1   |
+------+------+
|    1 | b    |
|    2 | bb   |
|    3 | c    |
+------+------+

and this happens

+------+------+------+
| id   | f1   | f1   |
+------+------+------+
|    1 | a    | b    |
|    2 | aa   | bb   |
| NULL | NULL | c    |
+------+------+------+

Guess the last case will require a program to build a table that uses just a union, reads the result and merges the fields by id.