I'm learning oracle sql.
I'm just trying to display all the employees first name from 'Employee' table in single line with comma separation.
ex: john,alex,rosy
I'm using SQL*Plus for running the query.
You have to use some built in function like:
SYS_CONNECT_BY_PATH , ROW_NUMBER () OVER
Here is the solution
SQL>
SQL> create table test(id int, name varchar(10));
Table created
SQL> begin
2 insert into test values(1,'john');
3 insert into test values(2,'alex');
4 insert into test values(3,'rosy');
5 end;
6 /
PL/SQL procedure successfully completed
SQL> select listagg(name ,',') within group(order by id) result from test;
RESULT
--------------------------------------------------------------------------------
john,alex,rosy
SQL> drop table test purge;
Table dropped
SQL>
Related
How can I get the table name inside trigger function?
Something similar to TG_TABLE_NAME in Postgres, like this
Oracle 10g or above.
That's user_triggers view (if I understood the question correctly).
SQL> create table test (id number, name varchar2(20));
Table created.
SQL> create or replace trigger trg_test
2 before insert on test
3 for each row
4 begin
5 null;
6 end;
7 /
Trigger created.
SQL> select trigger_name, table_name from user_triggers;
TRIGGER_NAME TABLE_NAME
------------------------------ ------------------------------
TRG_TEST TEST --> this is the one I've just created
TRG_AIUD_EMP EMPLOYEES
SQL>
I have these 4 tables:
Suppliers( id_sup, name, city)
Products (id_prod, name, city)
Companies (id_co, name, city)
Deliveries (id_sup, id_prod, id_co)
I created a view for Deliveries called "v_deliveries" and I want to create an instead of trigger so that if someone tries inserting data in the view, it will actually add it to the Deliveries table. This is what i've tried:
CREATE OR REPLACE TRIGGER new_deliv_trigg
INSTEAD OF INSERT ON v_deliveries FOR EACH ROW
BEGIN
INSERT INTO Deliveries (id_sup, id_prod, id_co)
VALUES (:NEW.id_sup, :NEW.id_prod, :NEW.id_co);
End;
Which database do you really use? Because, as for Oracle, it works OK:
SQL> create table deliveries (id_sup number, id_prod number, id_co number);
Table created.
SQL> create or replace view v_deliveries as select * From deliveries;
View created.
SQL>
SQL> CREATE OR REPLACE TRIGGER new_deliv_trigg
2 INSTEAD OF INSERT ON v_deliveries FOR EACH ROW
3 BEGIN
4 INSERT INTO Deliveries (id_sup, id_prod, id_co)
5 VALUES (:NEW.id_sup, :NEW.id_prod, :NEW.id_co);
6 End;
7 /
Trigger created.
SQL>
How I do create column ID with value JASG1?
I am only find example like this :
select 'JASG'||to_char(mtj_id_seq.nextval) from talend_job
Although what you wrote probably works (if there's a sequence named MTJ_ID_SEQ, you have a privilege to select from it; the same goes for the TALEND_JOB table), I'd say that it isn't what you should use.
Here's why: I'll create a table and a sequence. Table will be pre-populated with some IDs (just to put something in there).
SQL> create sequence mtj_id_seq;
Sequence created.
SQL> create table talend_job as
2 select rownum id from dept;
Table created.
SQL> select * from talend_job;
ID
----------
1
2
3
4
OK; 4 rows so far. Now, run your SELECT:
SQL> select 'JASG'||to_char(mtj_id_seq.nextval) from talend_job;
'JASG'||TO_CHAR(MTJ_ID_SEQ.NEXTVAL)
--------------------------------------------
JASG1
JASG2
JASG3
JASG4
SQL> select 'JASG'||to_char(mtj_id_seq.nextval) from talend_job;
'JASG'||TO_CHAR(MTJ_ID_SEQ.NEXTVAL)
--------------------------------------------
JASG5
JASG6
JASG7
JASG8
SQL>
See? You didn't get only 1 JASGx value, but as many as number of rows in the TALEND_JOB table. If there was a million rows, you'd get a million JASGx rows as well.
Therefore, maybe you meant to use DUAL table instead? E.g.
SQL> select 'JASG'||to_char(mtj_id_seq.nextval) from dual;
'JASG'||TO_CHAR(MTJ_ID_SEQ.NEXTVAL)
--------------------------------------------
JASG9
SQL> select 'JASG'||to_char(mtj_id_seq.nextval) from dual;
'JASG'||TO_CHAR(MTJ_ID_SEQ.NEXTVAL)
--------------------------------------------
JASG10
SQL>
See? Only one value.
Also, notice that sequences will provide unique values, but you can't rely on them being gapless.
As you mentioned "how to create column ID" - one option is to use a trigger. Here's an example:
SQL> create table talend_job (id varchar2(20), name varchar2(20)
Table created.
SQL> create or replace trigger trg_bi_tj
2 before insert on talend_job
3 for each row
4 begin
5 :new.id := 'JASG' || mtj_id_seq.nextval;
6 end;
7 /
Trigger created.
Let's insert some names; IDs should be auto-populated by the trigger:
SQL> insert into talend_job (name) values ('littlefoot');
1 row created.
SQL> insert into talend_job (name) values ('Ishak');
1 row created.
SQL> select * From talend_job;
ID NAME
-------------------- --------------------
JASG11 littlefoot
JASG12 Ishak
SQL>
OK then; now you have some more info - read and think about it.
By the way, what is the "compiler-errors" tag used for? Did you write any code and it failed? Perhaps you'd want to share it with us.
I have a table with many columns, and what I would like to do is duplicate all of the rows in the table, but also update one of the columns to a new value.
For example lets say I have the table below. I want to add to my table a duplicate of each row, except instead of BASIC access, it will have 'ADVANCED':
Before:
NAME, GENDER, ACCESS
----------------------
STEVE, MALE, BASIC
MOLLY, FEMALE, BASIC
After
NAME, GENDER, ACCESS
----------------------
STEVE, MALE, BASIC
MOLLY, FEMALE, BASIC
STEVE, MALE, ADVANCED
MOLLY, FEMALE, ADVANCED
Is there a way to do this without specifying all columns? I have 60 columns in the table, and the structure can change (meaning columns may be added, removed, renamed, etc).
Is it possible in Oracle SQL to automate this?
Just use insert . . . select:
insert into t (name, gender, access)
select name, gender, 'ADVANCED'
from t;
You need to list all the columns. You can shorten the manual process by using a query to generate the list. If you had to do this a lot and always knew you were leaving out access and access is the last column, you could use a view:
create view v_t as
select . . . -- all but access
from t;
insert into t ( . . . )
select v.*, 'ADVANCED'
from v_t;
Or you could use dynamic SQL to generate the statement.
However, I don't recommend any of those. Instead I would be concerned about a data model where you are regularly adding and modifying the columns in a table. That sounds dangerous.
Without specifying all the columns? With some help of a "temporary" table, here's how:
Your current table:
SQL> create table test
2 (name varchar2(10),
3 gender varchar2(20),
4 caccess varchar2(20));
Table created.
SQL> insert into test
2 select 'steve', 'male', 'basic' from dual union all
3 select 'molly', 'female', 'basic' from dual;
2 rows created.
Create a "temporary" table as a copy of the "original" table
update column you want to modify
copy the whole "temporary" table to the "original"
drop the "temporary" table
SQL> create table test_temp as select * From test;
Table created.
SQL> update test_temp set caccess = 'advanced';
2 rows updated.
SQL> insert into test select * From test_temp;
2 rows created.
SQL> drop table test_Temp;
Table dropped.
SQL> select * From test;
NAME GENDER CACCESS
---------- -------------------- --------------------
steve male basic
molly female basic
steve male advanced
molly female advanced
SQL>
Apparently, that works, but - what if the original table is huge? It takes a lot of space, and its copy takes approximately twice as much. Why are you doing that, anyway?
Try below method with anonymous block to avoid listing columns in insert statements
CREATE TABLE ACCESS_CHN
(NAAME VARCHAR2(100),
GENDER VARCHAR2(20),
ACCCESS VARCHAR2(30))
INSERT into ACCESS_CHN values('STEVE','MALE','BASIC');
INSERT into ACCESS_CHN values('MOLLY','FEMALE','BASIC');
COMMIT;
DECLARE
column_list varchar2(2000):=NULL;
plsql_block VARCHAR2(1000);
BEGIN
select LISTAGG(column_name,',') within group (order by column_id)
into column_list
from user_tab_columns
where table_name='ACCESS_CHN';
plsql_block := 'CREATE TABLE ACCESS_CHN_BKP as select '|| column_list || ' from ACCESS_CHN';
EXECUTE IMMEDIATE plsql_block;
plsql_block := 'UPDATE ACCESS_CHN_BKP set ACCCESS=''ADVANCED'' ';
EXECUTE IMMEDIATE plsql_block;
COMMIT;
plsql_block := 'CREATE TABLE ACCESS_CHN_FINAL as select * from ACCESS_CHN
union all
select * from ACCESS_CHN_BKP';
EXECUTE IMMEDIATE plsql_block;
END;
--To rerun drop tables ACCESS_CHN_BKP and ACCESS_CHN_FINAL
We generate tables dynamically Eg. Table T_1, T_2, T_3, etc & we can get that table names from another table by following query.
SELECT CONCAT('T_', T_ID) AS T_NAME FROM T_NAMES WHERE T_KEY = 'ABC';
Now I want to get records from this retrieved table name. What can I do ?
I'm doing like following but that's not working :
SELECT * FROM (SELECT CONCAT('T_', T_ID) AS T_NAME FROM T_NAMES WHERE T_KEY = 'ABC')
FYI : I'm hitting two individual queries as of now though I want to eliminate one and I can not follow cursor/procedure approach due to some limitations.
A procedure which utilizes refcursor seems to be the most appropriate to me. Here's an example:
SQL> -- creating test case (your T_NAMES table and T_1 which looks like Scott's DEPT)
SQL> create table t_names (t_id number, t_key varchar2(3));
Table created.
SQL> insert into t_names values (1, 'ABC');
1 row created.
SQL> create table t_1 as select * from dept;
Table created.
SQL> -- a procedure; accepts KEY and returns refcursor
SQL> create or replace procedure p_test
2 (par_key in varchar2, par_out out sys_refcursor)
3 as
4 l_t_name varchar2(30);
5 begin
6 select 'T_' || t_id
7 into l_t_name
8 from t_names
9 where t_key = par_key;
10
11 open par_out for 'select * from ' || l_t_name;
12 end;
13 /
Procedure created.
OK, let's test it:
SQL> var l_out refcursor
SQL> exec p_test('ABC', :l_out)
PL/SQL procedure successfully completed.
SQL> print l_out
DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON
SQL>
I could propose to you Dynamic SQL.
First of all, you need to create a cursor. The cursor will iterate by the dynamic tables. Then you could use dynamic SQL to create a query and then execute it.
So example:
https://livesql.oracle.com/apex/livesql/file/content_C81136WLRFYZF8ION6Q57GWE1.html - detailed cursor example.
https://docs.oracle.com/cd/B28359_01/appdev.111/b28370/dynamic.htm#i13057 - dynamic SQL in Oracle