Ggtcf

in SQL Developer, i want to select only one row from my table (with all attibute values) of each different value.
It's not important what row is selected for each type, what matters is to select only one row for type.

for example i have this table:

| A | B | C |
 X SS G
 Y SB T
 Z SB T

Note that in my table there aren't numbers.

The result i want is:

| A | B | C |
 X SS G
 Z SB T

But is correct also

| A | B | C |
 X SS G
 Y SB T

Thank you!

It isn't very clear what you want. You could get your result just with

Select distinct top 2 * from mytable

You want only 1 row from the rows with c = 'T', right?

select a, b, c from tablename where c <> 'T'
union all
select a, b, c from (
 select a, b, c from tablename where c = 'T'
) where rownum <= 1 

You probably need to use GROUP BY and then aggregate column A into a new comma separated string. Use this for the group by:

SELECT B,C FROM your_table GROUP BY B,C

This will output:

+---+---+
| B| C|
+---+---+
| SS| G|
| SB| T|
+---+---+

Then you need to collect somehow the aggregated results of A into a string containing all the values for the specific row:

mysql

SELECT B,C,GROUP_CONCAT(A) as A_STRING FROM tmp GROUP BY B,C;

PostgreSQL

SELECT B,C,string_agg(A, ',') as A_STRING FROM tmp GROUP BY B,C;

SQL Server

SELECT B,C,STRING_AGG(A, ',') as A_STRING FROM tmp GROUP BY B,C;

Then the output will be:

+---+---+--------+
| B| C|A_STRING|
+---+---+--------+
| SS| G|X |
| SB| T|Y,Z |
+---+---+--------+

Hence a new string per row.

You can use the below if the value of A is not important

SELECT max(A) as A,B,C FROM your_table GROUP BY B,C

Thank you to all for your answers, but I solved in this way:

SELECT MAX(A), B, MAX(C)
FROM MY_TABLE
GROUP BY B;

With this query I can extract all values for each different type of B.
I hope this will be helpful for someone.