CODEWITHSUNDEEP
sqloracle-databaseoracle11g
user11736392
user11736392

Reputation:

showing columns with Oracle SQL

I work with tables that have lots of columns that don't fit on my screen. When I create SQL I am really looking at a few columns worth of information.

What is a better way of moving a column from the right side to the first left most column? That way my results will show the column I am interested in first.

Currently I am using 

Select ColumnNumber201, t.*
from TableName t

I have a feeling this will add extra results to my query if I was concerned about counts, because it is a join. I would like avoid joins if possible.

Thanks for your help in advance.

We are using Oracle DB SQL

Upvotes: 0

Views: 33

Answers (1)

Littlefoot
Littlefoot

Reputation: 143103

Well, this is the way to display columns you're interested in - name them. In order to put them to the "front" (i.e. to be the leftmost), do exactly what you are doing.

I don't understand your concern about counts. What "join" are you talking about? There's no join in a statement you posted. This:

Select ColumnNumber201, t.*
from TableName t

selects only from one table.

Even if you join it to another table, it is the join condition and where clause that matters, not number of columns you select (OK, aggregates change things, but that's another story).

For example:

SQL> select count(*) one_column_one_table
  2  from (select e.ename
  3        from emp e);

ONE_COLUMN_ONE_TABLE
--------------------
                  14

SQL>
SQL> select count(*) many_columns_one_table
  2  from (select e.ename, e.*
  3        from emp e);

MANY_COLUMNS_ONE_TABLE
----------------------
                    14

SQL>
SQL> select count(*) many_columns_two_tables
  2  from (select d.dname, e.ename, e.*, d.*
  3        from emp e join dept d on e.deptno = d.deptno);

MANY_COLUMNS_TWO_TABLES
-----------------------
                     14

SQL>
SQL> select count(*) many_columns_two_tables_where
  2  from (select d.dname, e.ename, e.*, d.*
  3        from emp e join dept d on e.deptno = d.deptno
  4        where d.deptno = 20);

MANY_COLUMNS_TWO_TABLES_WHERE
-----------------------------
                            5

SQL>

Upvotes: 1

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