Problem: I want to get an average salary of all employees. The query itself is rather simple:
Question: Is it possible to move COUNT(salary) to selected column's title (after AS statement), so the name of the column will be "Average salary of 20 employees"? I've been trying several approaches, but none of them worked. I would really appreciate any help. Thank you in advance.
Screenshot you posted looks like Apex SQL Workshop. I don't know how to do it there, but - if you used SQL*Plus, then you could do something like this (not exactly as you wanted it, though):
SQL> set ver off
SQL> column cnt_emps new_value l_cnt
SQL> select count(*) cnt_emps from emp;
CNT_EMPS
----------
14
SQL> select avg(sal) as "Average salary of &l_cnt employees" from emp;
Average salary of 14 employees
--------------------------------------
2073.21429
SQL>
However, if you're already using Apex, switch to GUI and create a page which will let you format the result any way you want (using colors, large font, bold letters, whatever). SQL*Plus and its descendants are kind of restrictive when such things should be done.
I created a random View like this:
CREATE OR REPLACE NOFORCE VIEW TEMP_VIEW (first_name, age) AS
SELECT 'Gladiolus' first_name, 23 age
FROM dual
/
And I check it out:
SELECT * FROM temp_view
/
FIRST_NAME AGE
---------- ----------
Gladiolus 23
Now, when I open the source to edit it (with PLSQL Developer and SQL Navigator) I get this:
CREATE OR REPLACE VIEW TEMP_VIEW AS
SELECT 'Gladiolus' first_name, 23 age
FROM dual;
The alias (first_name, age) is ommited because they are equal to the columns of the subquery.
But can you tell me why the clause NOFORCE is also not showed?
Thank you!!
Some keywords control how objects are created but they are not a part of the object definition. Oracle does not always care "how" an object was created and does not always store the options used to create it.
When Oracle and 3rd party tools create a DDL statement they must guess which of those options you would like to use. It's not uncommon for the tools to make different guesses, or to have small syntax differences.
(This is one of the many reasons to store all DDL in version-controlled text files instead of the database. What you put into the database will NOT be the same as what you get out.)
To use your example another way:
SQL> CREATE NOFORCE VIEW TEMP_VIEW (first_name, age) AS
2 SELECT 'Gladiolus' first_name, 23 age
3 FROM dual
4 /
View created.
The view was created with NOFORCE and without an OR REPLACE. But the DDL generated by DBMS_METADATA.GET_DDL contains FORCE, OR REPLACE and other differences:
SQL> select dbms_metadata.get_ddl('VIEW', 'TEMP_VIEW') from dual;
DBMS_METADATA.GET_DDL('VIEW','TEMP_VIEW')
--------------------------------------------------------------------------------
CREATE OR REPLACE FORCE EDITIONABLE VIEW "JHELLER"."TEMP_VIEW" ("FIRST_NAME",
"AGE") AS
SELECT 'Gladiolus' first_name, 23 age
FROM dual
The real "source" of the object does not contain any of the CREATE options at all:
SQL> select text from dba_views where view_name = 'TEMP_VIEW';
TEXT
--------------------------------------------------------------------------------
SELECT 'Gladiolus' first_name, 23 age
FROM dual
Here's an incomplete list of things that may be different when you regenerate code from an Oracle databases:
OR REPLACE
FORCE|NOFORCE
AND RESOLVE|AND COMPILE (for Java)
Whitespace
Case
Column Lists
Double Quotes
Terminators
Different DDL generators allow you to control some of those options, but in my experience none of them let you completely control all of them.
NOFORCE is the default, so keeping it is redundant.
I created like 20 tables in sql 11g and lost the record of them. Is there any way I can list the table names I created.
SELECT table_name FROM user_tables is not the solution.
First, log on as sys before you can view the tables in the entire database.
Second, run this query using the sys
SELECT owner, table_name FROM dba_tables WHERE owner='HR';
This should display all tables owned by the HR schema. Remember to use uppercase for the owner (HR) else you will receive error.
Hope this helps.
The Best approach to solve this issue is considering the attribute of ALL_ALL_TABLES named
LAST_ANALYZED
It gives Date on which the table was most recently analyzed.
So you could easily query the database with the help of DATE Functions.
The Oracle Database Reference helps you.
SELECT TABLE_NAME FROM USER_ALL_TABLES
Well, if user_all_tables is not your desired result, you will have to rely on dba_tables via:
SELECT owner, table_name
FROM dba_tables
But for this you need more privs than for user_tables obviously
How do I query an Oracle database to display the names of all tables in it?
SELECT owner, table_name
FROM dba_tables
This is assuming that you have access to the DBA_TABLES data dictionary view. If you do not have those privileges but need them, you can request that the DBA explicitly grants you privileges on that table, or, that the DBA grants you the SELECT ANY DICTIONARY privilege or the SELECT_CATALOG_ROLE role (either of which would allow you to query any data dictionary table). Of course, you may want to exclude certain schemas like SYS and SYSTEM which have large numbers of Oracle tables that you probably don't care about.
Alternatively, if you do not have access to DBA_TABLES, you can see all the tables that your account has access to through the ALL_TABLES view:
SELECT owner, table_name
FROM all_tables
Although, that may be a subset of the tables available in the database (ALL_TABLES shows you the information for all the tables that your user has been granted access to).
If you are only concerned with the tables that you own, not those that you have access to, you could use USER_TABLES:
SELECT table_name
FROM user_tables
Since USER_TABLES only has information about the tables that you own, it does not have an OWNER column – the owner, by definition, is you.
Oracle also has a number of legacy data dictionary views-- TAB, DICT, TABS, and CAT for example-- that could be used. In general, I would not suggest using these legacy views unless you absolutely need to backport your scripts to Oracle 6. Oracle has not changed these views in a long time so they often have problems with newer types of objects. For example, the TAB and CAT views both show information about tables that are in the user's recycle bin while the [DBA|ALL|USER]_TABLES views all filter those out. CAT also shows information about materialized view logs with a TABLE_TYPE of "TABLE" which is unlikely to be what you really want. DICT combines tables and synonyms and doesn't tell you who owns the object.
Querying user_tables and dba_tables didn't work.
This one did:
select table_name from all_tables
Going one step further, there is another view called cols (all_tab_columns) which can be used to ascertain which tables contain a given column name.
For example:
SELECT table_name, column_name
FROM cols
WHERE table_name LIKE 'EST%'
AND column_name LIKE '%CALLREF%';
to find all tables having a name beginning with EST and columns containing CALLREF anywhere in their names.
This can help when working out what columns you want to join on, for example, depending on your table and column naming conventions.
For better viewing with sqlplus
If you're using sqlplus you may want to first set up a few parameters for nicer viewing if your columns are getting mangled (these variables should not persist after you exit your sqlplus session ):
set colsep '|'
set linesize 167
set pagesize 30
set pagesize 1000
Show All Tables
You can then use something like this to see all table names:
SELECT table_name, owner, tablespace_name FROM all_tables;
Show Tables You Own
As #Justin Cave mentions, you can use this to show only tables that you own:
SELECT table_name FROM user_tables;
Don't Forget about Views
Keep in mind that some "tables" may actually be "views" so you can also try running something like:
SELECT view_name FROM all_views;
The Results
This should yield something that looks fairly acceptable like:
Simple query to select the tables for the current user:
SELECT table_name FROM user_tables;
select object_name from user_objects where object_type='TABLE';
----------------OR------------------
select * from tab;
----------------OR------------------
select table_name from user_tables;
Try the below data dictionary views.
tabs
dba_tables
all_tables
user_tables
Execute the below commands:
Show all tables in the Oracle Database
sql> SELECT table_name FROM dba_tables;
Show tables owned by the current user
sql> SELECT table_name FROM user_tables;
Show tables that are accessible by the current user
sql> SELECT table_name FROM all_tables ORDER BY table_name;
Oracle database to display the names of all tables using below query
SELECT owner, table_name FROM dba_tables;
SELECT owner, table_name FROM all_tables;
SELECT table_name FROM user_tables;
vist more : http://www.plsqlinformation.com/2016/08/get-list-of-all-tables-in-oracle.html
Try selecting from user_tables which lists the tables owned by the current user.
With any of those, you can select:
SELECT DISTINCT OWNER, OBJECT_NAME
FROM DBA_OBJECTS
WHERE OBJECT_TYPE = 'TABLE' AND OWNER='SOME_SCHEMA_NAME';
SELECT DISTINCT OWNER, OBJECT_NAME
FROM ALL_OBJECTS
WHERE OBJECT_TYPE = 'TABLE' AND OWNER='SOME_SCHEMA_NAME';
select * from dba_tables
gives all the tables of all the users only if the user with which you logged in is having the sysdba privileges.
I did not find answer which would point to use
DBA_ALL_TABLES (ALL_ALL_TABLES/USER_ALL_TABLES)
so decided to add my version as well.
This view actually returns more that DBA_TABLES as it returns object tables as well (http://docs.oracle.com/cd/E11882_01/server.112/e40402/statviews_1003.htm).
A new feature available in SQLcl( which is a free command line interface for Oracle Database) is
Tables alias.
Here are few examples showing the usage and additional aspects of the feature. First, connect to a sql command line (sql.exe in windows) session. It is recommended to enter this sqlcl specific command before running any other commands or queries which display data.
SQL> set sqlformat ansiconsole -- resizes the columns to the width of the
-- data to save space
SQL> tables
TABLES
-----------
REGIONS
LOCATIONS
DEPARTMENTS
JOBS
EMPLOYEES
JOB_HISTORY
..
To know what the tables alias is referring to, you may simply use alias list <alias>
SQL> alias list tables
tables - tables <schema> - show tables from schema
--------------------------------------------------
select table_name "TABLES" from user_tables
You don't have to define this alias as it comes by default under SQLcl. If you want to list tables from a specific schema, using a new user-defined alias and passing schema name as a bind argument with only a set of columns being displayed, you may do so using
SQL> alias tables_schema = select owner, table_name, last_analyzed from all_tables where owner = :ownr;
Thereafter you may simply pass schema name as an argument
SQL> tables_schema HR
OWNER TABLE_NAME LAST_ANALYZED
HR DUMMY1 18-10-18
HR YOURTAB2 16-11-18
HR YOURTABLE 01-12-18
HR ID_TABLE 05-12-18
HR REGIONS 26-05-18
HR LOCATIONS 26-05-18
HR DEPARTMENTS 26-05-18
HR JOBS 26-05-18
HR EMPLOYEES 12-10-18
..
..
A more sophisticated pre-defined alias is known as Tables2, which displays several other columns.
SQL> tables2
Tables
======
TABLE_NAME NUM_ROWS BLOCKS UNFORMATTED_SIZE COMPRESSION INDEX_COUNT CONSTRAINT_COUNT PART_COUNT LAST_ANALYZED
AN_IP_TABLE 0 0 0 Disabled 0 0 0 > Month
PARTTABLE 0 0 0 1 0 1 > Month
TST2 0 0 0 Disabled 0 0 0 > Month
TST3 0 0 0 Disabled 0 0 0 > Month
MANAGE_EMPLYEE 0 0 0 Disabled 0 0 0 > Month
PRODUCT 0 0 0 Disabled 0 0 0 > Month
ALL_TAB_X78EHRYFK 0 0 0 Disabled 0 0 0 > Month
TBW 0 0 0 Disabled 0 0 0 > Month
DEPT 0 0 0 Disabled 0 0 0 > Month
To know what query it runs in the background, enter
alias list tables2
This will show you a slightly more complex query along with predefined column definitions commonly used in SQL*Plus.
Jeff Smith explains more about aliases here
You can use Oracle Data Dictionary to get information about oracle objects.
You can get list of tables in different ways:
select *
from dba_tables
or for example:
select *
from dba_objects
where object_type = 'TABLE'
Then you can get table columns using table name:
select *
from dba_tab_columns
Then you can get list of dependencies (triggers, views and etc.):
select *
from dba_dependencies
where referenced_type='TABLE' and referenced_name=:t_name
Then you can get text source of this objects:
select * from dba_source
And you can use USER or ALL views instead of DBA if you want.
We can get all tables including column details from below query:
SELECT * FROM user_tab_columns;
Including views:
SELECT owner, table_name as table_view
FROM dba_tables
UNION ALL
SELECT owner, view_name as table_view
FROM DBA_VIEWS
Below is a commented snippet of SQL queries describing how options you can make use of:
-- need to have select catalog role
SELECT * FROM dba_tables;
-- to see tables of your schema
SELECT * FROM user_tables;
-- tables inside your schema and tables of other schema which you possess select grants on
SELECT * FROM all_tables;
The following query only list the required data, whereas the other answers gave me the extra data which only confused me.
select table_name from user_tables;
I was looking to get a list of all columns names belonging to a table of a schema sorted by the order of column id.
Here's the query I am using: -
SELECT COLUMN_NAME
FROM ALL_TAB_COLUMNS
WHERE OWNER = 'schema_owner_username' AND TABLE_NAME='table_name'
ORDER BY COLUMN_ID ASC;
Indeed, it is possible to have the list of tables via SQL queries.it is possible to do that also via tools that allow the generation of data dictionaries, such as ERWIN, Toad Data Modeler or ERBuilder. With these tools, in addition to table names, you will have fields, their types, objects like(triggers, sequences, domain, views...)
Below steps to follow to generate your tables definition:
You have to reverse engineer your database
In Toad data modeler: Menu -> File -> reverse engineer -> reverse engineering wizard
In ERBuilder data modeler: Menu -> File -> reverse engineer
Your database will be displayed in the software as an Entity Relationship diagram.
Generate your data dictionary that will contain your Tables definition
In Toad data modeler: Menu -> Model -> Generate report -> Run
In ERBuilder data modeler: Menu -> Tool -> generate model documentation
To get all the table names, we can use:
Select owner, table_name from all_tables;
if you have dba permission, you can use:
Select owner, table_name from dba_tables;
select * from all_all_tables
this additional 'all' at the beginning gives extra 3 columns which are:
OBJECT_ID_TYPE
TABLE_TYPE_OWNER
TABLE_TYPE
Tables in the current user - logon schema
select * from tabs;