In SQL Server we can use this:
DECLARE #variable INT;
SELECT #variable= mycolumn from myTable;
How can I do the same in Oracle? I'm currently attempting the following:
DECLARE COMPID VARCHAR2(20);
SELECT companyid INTO COMPID from app where appid='90' and rownum=1;
Why this is not working?
SELECT INTO
DECLARE
the_variable NUMBER;
BEGIN
SELECT my_column INTO the_variable FROM my_table;
END;
Make sure that the query only returns a single row:
By default, a SELECT INTO statement must return only one row. Otherwise, PL/SQL raises the predefined exception TOO_MANY_ROWS and the values of the variables in the INTO clause are undefined. Make sure your WHERE clause is specific enough to only match one row
If no rows are returned, PL/SQL raises NO_DATA_FOUND. You can guard against this exception by selecting the result of an aggregate function, such as COUNT(*) or AVG(), where practical. These functions are guaranteed to return a single value, even if no rows match the condition.
A SELECT ... BULK COLLECT INTO statement can return multiple rows. You must set up collection variables to hold the results. You can declare associative arrays or nested tables that grow as needed to hold the entire result set.
The implicit cursor SQL and its attributes %NOTFOUND, %FOUND, %ROWCOUNT, and %ISOPEN provide information about the execution of a SELECT INTO statement.
Not entirely sure what you are after but in PL/SQL you would simply
DECLARE
v_variable INTEGER;
BEGIN
SELECT mycolumn
INTO v_variable
FROM myTable;
END;
Ollie.
One Additional point:
When you are converting from tsql to plsql you have to worry about no_data_found exception
DECLARE
v_var NUMBER;
BEGIN
SELECT clmn INTO v_var FROM tbl;
Exception when no_data_found then v_var := null; --what ever handle the exception.
END;
In tsql if no data found then the variable will be null but no exception
ORA-01422: exact fetch returns more than requested number of rows
if you don't specify the exact record by using where condition, you will get the above exception
DECLARE
ID NUMBER;
BEGIN
select eid into id from employee where salary=26500;
DBMS_OUTPUT.PUT_LINE(ID);
END;
For storing a single row output into a variable from the select into query :
declare v_username varchare(20);
SELECT username into v_username FROM users WHERE user_id = '7';
this will store the value of a single record into the variable v_username.
For storing multiple rows output into a variable from the select into query :
you have to use listagg function. listagg concatenate the resultant rows of a coloumn into a single coloumn and also to differentiate them you can use a special symbol.
use the query as below
SELECT listagg(username || ',' ) within group (order by username) into v_username FROM users;
Related
declare
vquery long;
cursor c1 is
select * from temp_name;
begin
for i in c1
loop
vquery :='INSERT INTO ot.temp_new(id)
select '''||i.id||''' from ot.customers';
dbms_output.put_line(i.id);
end loop;
end;
/
Output of select * from temp_name is :
ID
--------------------------------------------------------------------------------
customer_id
1 row selected.
I have customers table which has customer_id column.I want to insert all the customer_id into temp_new table but it is not being inserted. The PLSQL block executes successfully but the temp_new table is empty.
The output of dbms_output.put_line(i.id); is
customer_id
What is wrong there?
The main problem is that you generate a dynamic statement that you never execute; at some point you need to do:
execute immediate vquery;
But there are other problems. If you output the generated vquery string you'll see it contains:
INSERT INTO ot.temp_new(id)
select 'customer_id' from ot.customers
which means that for every row in customers you'll get one row in temp_new with ID set to the same fixed literal 'customer_id'. It's unlikely that's what you want; if customer_id is a column name from customers then it shouldn't be in single quotes.
As #mathguy suggested, long is not a sensible data type to use; you could use a CLOB but only really need a varchar2 here. So something more like this, where I've also switched to use an implicit cursor:
declare
l_stmt varchar2(4000);
begin
for i in (select id from temp_name)
loop
l_stmt := 'INSERT INTO temp_new(id) select '||i.id||' from customers';
dbms_output.put_line(i.id);
dbms_output.put_line(l_stmt);
execute immediate l_stmt;
end loop;
end;
/
db<>fiddle
The loop doesn't really make sense though; if your temp_name table had multiple rows with different column names, you'd try to insert the corresponding values from those columns in the customers table into multiple rows in temp_new, all in the same id column, as shown in this db<>fiddle.
I guess this is the starting point for something more complicated, but still seems a little odd.
Hello again I need some help,
I have table where in column "query" is defined query statement. I would like to run it and as output get the result.For example:
Create table table1
(
ID Number,
Query Varchar2(400)
)
insert into table1(id,query) values (1,'select name from table2 where table2.id=table1.id and table2.type = variable');
create table table2
(ID number,
Name varchar2(400),
Type Varchar2(400)
)
insert into table2 values (1,'Mathew','M');
insert into table2 values (1,'Thomas','G');
insert into table2 values (2,'Jerry','P');
For now query :
'select name from table2 where table2.id=table1.id and table2.type = variable'
should return only "Mathew" (assuming variable as 'M' - procedure variable input)
As procedure input I want to have variable which I will replace somehow in query statement.
Could you give me some tips how to handle with that?
------------Edit
I did stmh like that:
create or replace procedure queryrun
(var1 varchar2) as
str VARCHAR2(200);
BEGIN
execute immediate 'select replace(query,''variable'','''||var1||''') from table1' into str;
dbms_output.put_line('Value is '||str);
END;
But as result it present query... no result of select statement...
You are only selecting your query, not running it; and you're replacing the string "'variable'" - including the single quotes - with your value, but your original query string doesn't have the single quotes around it - so nothing matches.
You should not really substitue a hard-coded value anyway. Change your stored query to include a bind variable placeholder instead:
insert into table1(id,query)
values (1,'select name from table2 where table2.id=table1.id and table2.type = :variable');
Although that query is invalid anyway - you don't have table1 defined in the from clause or a join clause. When you have a valid query you can run standalone, use that, but with a bind variable (denoted by the leading colon).
But let's assume you have a valid query string in your table, that will only return one row, say:
insert into table1(id,query)
values (1,'select name from table2 where type = :variable');
Your procedure then needs a local variable to hold that query string. You select your query into that using static SQL, and then use dynamic SQL via execute immediate to run the query from that string, and provide the bind value with the using clause. The result goes into another local variable, which you are already doing.
So a simple version might look like this:
create or replace procedure queryrun (p_var1 varchar2) as
l_query table1.query%type;
l_name table2.name%type;
begin
select query into l_query from table1 where id = 1;
execute immediate query into l_name using p_var1;
dbms_output.put_line('Value is ' || l_name);
end;
This is obviously rather contrived. If you have multiple queries in your table, and perhaps pass a second ID variable into the procedure to choose which one to run, they would all have to take a single bind variable, and would have to all be able to put the result into the same type and size of result variable. You're also restricted to queries that return exactly one row. You can adapt and extend this of course, but hopefully this will get you started.
You can have bind variable and use plsql execute immediate.
Examples:
http://www.dba-oracle.com/t_oracle_execute_immediate.htm
create or replace
trigger addpagamento
after insert on marcacoes_refeicoes
for each row
declare
nmarcacaoa number;
ncartaoa number;
begin
select nmarcacao into nmarcacaoa from marcacoes_refeicoes where rownum < (select count(*) from marcacoes_refeicoes);
select ncartao into ncartaoa from marcacoes_refeicoes where rownum < (select count(*) from marcacoes_refeicoes);
insert_pagamentos(nmarcacaoa, ncartaoa); --this is a procedure
exception when others then
raise_application_error(-20001, 'Error in Trigger!!!');
end addpagamento;
when i try to run the insert statement to the table "marcacoes_refeicoes" this procedure gives error: like the table is mutating
create or replace
procedure insert_pagamentos
(nmarcacaoa in number, ncartaoa in number)
AS
BEGIN
insert into pagamentos (nmarcacao, datapagamento, ncartao) values (nmarcacaoa, sysdate, ncartaoa);
commit;
END INSERT_PAGAMENTOS;
Short (oversimplified) answer:
You can't modify a table in a trigger that changes the table.
Long answer:
http://www.oracle-base.com/articles/9i/mutating-table-exceptions.php has a more in-depth explanation, including suggestions how to work around the problem.
You're hitting the mutating-table problem because you're selecting from the same table the trigger is on, but what you seem to be trying to do doesn't make sense. Your queries to get a value for nmarcacaoa and ncartaoa will return a no_data_found or too_many_rows error unless the table had exactly 2 rows in it before your insert:
select nmarcacao from marcacoes_refeicoes
where rownum < (select count(*) from marcacoes_refeicoes);
will return all rows except one; and the one that's excluded will be kind of random as you have no ordering. Though the state is undetermined within the trigger, so you can't really how many rows there are, and it won't let you do this query anyway. You won't normally be able to get a single value, anyway, and it's not obvious which value you actually want.
I can only imagine that you're trying to use the values from the row you are currently inserting, and putting them in your separate payments (pagamentos) table. If so there is a built-in mechanism to do that using correlation names, which lets you refer to the newly inserted row as :new (by default):
create or replace
trigger addpagamento
after insert on marcacoes_refeicoes
for each row
begin
insert_pagamentos(:new.nmarcacaoa, :new.ncartaoa);
end addpagamento;
The :new is referring to the current row, so :new.nmarcacaoa is the nmarcacaoa being inserted. You don't need to (and can't) get that value from the table itself. (Even with the suggested autonomous pragma, that would be a separate transaction and would not be able to see your newly inserted and uncommitted data).
Or you can just do the insert directly; not sure what the procedure is adding here really:
create or replace
trigger addpagamento
after insert on marcacoes_refeicoes
for each row
begin
insert into pagamentos(nmarcacao, datapagamento, ncartao)
values (:new.nmarcacaoa, sysdate, :new.ncartaoa);
end addpagamento;
I've removed the exception handler as all it was doing was masking the real error, which is rather unhelpful.
Editing this answer in view of the comments below:
You can use PRAGMA AUTONOMOUS_TRANSACTION to get rid of the error, but DONOT USE it as it will NOT solve any purpose.
Use PRAGMA AUTONOMOUS_TRANSACTION:
create or replace
trigger addpagamento
after insert on marcacoes_refeicoes
for each row
declare
PRAGMA AUTONOMOUS_TRANSACTION;
nmarcacaoa number;
ncartaoa number;
begin
select nmarcacao into nmarcacaoa from marcacoes_refeicoes where rownum < (select count(*) from marcacoes_refeicoes);
select ncartao into ncartaoa from marcacoes_refeicoes where rownum < (select count(*) from marcacoes_refeicoes);
insert_pagamentos(nmarcacaoa, ncartaoa); --this is a procedure
exception when others then
raise_application_error(-20001, 'Error in Trigger!!!');
end addpagamento;
However in this case , select count(*) from marcacoes_refeicoes will give you the new count after the current insertion into the table.
I can't able to create a select statement in oracle procedure. Please help me to create this.
Now I create the insert,update.delete statement in a procedure but i can't create a select statement. Please help me to create the select statement using cursor.
c_dbuser OUT SYS_REFCURSOR
ELSIF (TYPE_ =1) THEN
OPEN c_dbuser FOR
SELECT * FROM tbl_discount_master ;
CLOSE c_dbuser;
END IF;
call procedure_name(xx,xx,xx,1);
how can i get the selected value using call procedure statement.
In addition to the other suggestion, you have this solution when you are getting exactly one row.
DECLARE
myvar1 mytable.mycolumn1%TYPE;
myvar2 mytable.mycolumn2%TYPE;
BEGIN
SELECT mycolumn1, mycolumn2
INTO myvar1, myvar2
FROM mytable
WHERE …;
END;
This will throw an exception if there is no selected row (NO_DATA_FOUND) or if there is more than one row (TOO_MANY_ROWS).
The difference between select and the insert/update/delete is that you need to select into some structure, either one or more variables or a rowtype variable.
Avoid explicit cursors whenever possible in favour of the faster, less verbose and less error prone implicit cursor.
eg.
for cur_my_query in
select column1,
column2,
...
from ...
where ...
loop
refer here to cur_my_query or my_query.column1 etc
end loop
In SQL Server we can use this:
DECLARE #variable INT;
SELECT #variable= mycolumn from myTable;
How can I do the same in Oracle? I'm currently attempting the following:
DECLARE COMPID VARCHAR2(20);
SELECT companyid INTO COMPID from app where appid='90' and rownum=1;
Why this is not working?
SELECT INTO
DECLARE
the_variable NUMBER;
BEGIN
SELECT my_column INTO the_variable FROM my_table;
END;
Make sure that the query only returns a single row:
By default, a SELECT INTO statement must return only one row. Otherwise, PL/SQL raises the predefined exception TOO_MANY_ROWS and the values of the variables in the INTO clause are undefined. Make sure your WHERE clause is specific enough to only match one row
If no rows are returned, PL/SQL raises NO_DATA_FOUND. You can guard against this exception by selecting the result of an aggregate function, such as COUNT(*) or AVG(), where practical. These functions are guaranteed to return a single value, even if no rows match the condition.
A SELECT ... BULK COLLECT INTO statement can return multiple rows. You must set up collection variables to hold the results. You can declare associative arrays or nested tables that grow as needed to hold the entire result set.
The implicit cursor SQL and its attributes %NOTFOUND, %FOUND, %ROWCOUNT, and %ISOPEN provide information about the execution of a SELECT INTO statement.
Not entirely sure what you are after but in PL/SQL you would simply
DECLARE
v_variable INTEGER;
BEGIN
SELECT mycolumn
INTO v_variable
FROM myTable;
END;
Ollie.
One Additional point:
When you are converting from tsql to plsql you have to worry about no_data_found exception
DECLARE
v_var NUMBER;
BEGIN
SELECT clmn INTO v_var FROM tbl;
Exception when no_data_found then v_var := null; --what ever handle the exception.
END;
In tsql if no data found then the variable will be null but no exception
ORA-01422: exact fetch returns more than requested number of rows
if you don't specify the exact record by using where condition, you will get the above exception
DECLARE
ID NUMBER;
BEGIN
select eid into id from employee where salary=26500;
DBMS_OUTPUT.PUT_LINE(ID);
END;
For storing a single row output into a variable from the select into query :
declare v_username varchare(20);
SELECT username into v_username FROM users WHERE user_id = '7';
this will store the value of a single record into the variable v_username.
For storing multiple rows output into a variable from the select into query :
you have to use listagg function. listagg concatenate the resultant rows of a coloumn into a single coloumn and also to differentiate them you can use a special symbol.
use the query as below
SELECT listagg(username || ',' ) within group (order by username) into v_username FROM users;