I'm new to Oracle SQL Developer. I have a VFP background and I'm having a difficult time trying to use variables as I have done quite a few other applications. Define the variable, determine what the variable is (programmatically), then use the variable. I'm good with the first 2 but I cannot figure out how to use the variable. Create a procedure, write the select statement to a var string, output to a cursor? I've seen many examples but nothing I can use or I'm just not understanding the different concept. Here is the code I've started with.
declare
v_mydate DATE;
begin
select max(date_added) into v_mydate from TEST_TB;
DBMS_OUTPUT.put_line(TO_CHAR(v_mydate)); -- checking to see if the variable has been assigned. It has
create table test_banks as
SELECT DISTINCT
FIELD1,
FIELD2,
, DATE_APPEND
FROM TEST_TB
WHERE DATE_ADDED=V_MYDATE
end;
Field1 and Field2 will have many distinct combinations. I want them all that have the max(date_added) value.
DDL is not allowed here. DDL is the data definition language. CREATE TABLE is a DDL statement.
Try execute immediate, which is really inefficient.
declare
v_mydate DATE;
begin
select max(date_added) into v_mydate from TEST_TB;
DBMS_OUTPUT.put_line(TO_CHAR(v_mydate)); -- checking to see if the variable has been assigned. It has
EXECUTE IMMEDIATE
'create table test_banks as
SELECT DISTINCT
FIELD1,
FIELD2,
, DATE_APPEND
FROM TEST_TB
WHERE DATE_ADDED in (select max(date_added) from TEST_TB)';
end;
You need not use PLSQL to do this task,You can just create a view like the below
CREATE OR REPLACE VIEW VW_TEST_BANKS
AS SELECT DISTINCT field1, field2, date_append
FROM TEST_TB where date_added=(SELECT TRUNC(MAX(date_added)) FROM TEST_TB)
or if you want to test the use of variables in WHERE clause you can try the below
declare
v_mydate DATE;
begin
select max(date_added) into v_mydate from TEST_TB;
DBMS_OUTPUT.put_line(TO_CHAR(v_mydate)); -- checking to see if the variable has been assigned. It has
FOR REC in (SELECT DISTINCT FIELD1, FIELD2,, DATE_APPEND
FROM TEST_TB
WHERE DATE_ADDED = V_MYDATE) LOOP
DBMS_OUTPUT.put_line('field1 ' || rec.field1);
DBMS_OUTPUT.put_line('field2 ' || rec.field2);
DBMS_OUTPUT.put_line('date_append ' || rec.date_append);
END LOOP;
end;
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.
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;
not sure if this is possible at all but im trying to do this with as little manual work as possible.
I have a table with 150 columns based on different combinations of factors.
I wish to extract the column names where a certain certain string is inside the column name.
I have done the following which does this. This is a basic example of what I have
--Create the table
Create Table temp
(id number,
Fac1_Fac2_Fac_3_Fac4_Fac5 number,
Fac1_Fac6_Fac_3_Fac4_Fac5 number,
Fac1_Fac6_Fac_7_Fac4_Fac5 number,
Fac1_Fac9_Fac_3_Fac4_Fac5 number,
Fac1_Fac10_Fac_3_Fac4_Fac5 number,
Fac1_Fac2_Fac_3_Fac11_Fac5 number,
Fac1_Fac2_Fac_3_Fac4_Fac12 number,
Fac13_Fac2_Fac_3_Fac4_Fac5 number);
Insert into temp Values (1,35634,3243,343,564,56,4635,3,334);
Insert into temp Values (2,3434234,3243,343,564,56,435,3,34234);
Insert into temp Values (3,5555,3243,33,564,56,435,3,3434);
Insert into temp Values (4,34234,343,343,564,56,4335,3,34);
commit;
--Extract Column Names
Select * from (
Select COLUMN_NAME
from user_tab_cols
where lower(table_name) ='temp'
)
where column_name like '%FAC13%'
--This is what I want to automate.
Select id, FAC13_FAC2_FAC_3_FAC4_FAC5
From temp
--I want the column name to come fron the select statment above as there may be lots of names.
Basically, I want to select all the rows from my table that have Fac13 in the column name all in one query if possible.
Thanks
I do not think you can do that in one query. First, your extract column names query can be simplified to one query as a cursor, and then use a dynamic select statement as follows:
CREATE OR REPLACE proc_dyn_select IS
CURSOR c1 IS
SELECT column_name
FROM user_tab_cols
WHERE LOWER(table_name) ='temp' and column_name LIKE '%FAC13%';
cols c1%ROWTYPE;
sqlstmt VARCHAR2(2000);
BEGIN
OPEN c1;
LOOP
FETCH c1 into cols;
EXIT WHEN c1%NOTFOUND;
sqlstmt := sqlstmt ||cols.column_name||',';
END LOOP;
CLOSE c1;
sqlstmt := 'select '||substr(sqlstmt, 1, length(sqlstmt)-1)||' FROM temp';
EXECUTE IMMEDIATE sqlstmt;
EXCEPTION
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('error '||sqlerrm);
END;
/
Explanation
First, the cursor will store the columns that meet your conditions (to be from the table temp and the column names have the sub string FAC13. Then in execution section (after BEGIN), you will build your query dynamically using columns names stored in the cursor c1. With each round of the loop, a column name is added as a string and concatenated with a comma. So a string of columns will be built like this 'col1, col2, col3, ... coln,'. The string is stored in sqlstmt variable.
After the loop end, you amend the string to build sql statement, by adding the keywords SELECT, FROM and table name. However, we remove the last character of the sqlstmt variable, as it is an extra comma.
EXECUTE IMMEDIATE statement, will run the query stored in sqlstmt.
By using a procedure, you can always pass parameters, such that this procedure can perform any dynamic sql statement you want.
I have a hefty SQL statement with unions where code keeps getting re-used. I was hoping to find out if there is a way to re-use a single bind variable without repeating the variable to for "USING" multiple times.
The code below returns "not all variables bound" until I change the "USING" line to "USING VAR1,VAR2,VAR1;"
I was hoping to avoid that as I'm referring to :1 in both instances - any ideas?
declare
var1 number :=1;
var2 number :=2;
begin
execute immediate '
select * from user_objects
where
rownum = :1
OR rownum = :2
OR rownum = :1 '
using var1,var2;
end;
/
EDIT: For additional info, I am using dynamic SQL as I also generate a bundle of where conditions.
I'm not great with SQL arrays (I am using a cursor in my code but I think that will overcomplicate the issue) but the pseudocode is:
v_where varchar2(100) :='';
FOR i in ('CAT','HAT','MAT') LOOP
v_where := v_where || ' OR OBJECT_NAME LIKE ''%' || i.string ||'%''
END;
v_where := ltrim(v_where, ' OR');
And then modifying the SQL above to something like :
execute immediate '
select * from user_objects
where
rownum = :1
OR rownum = :2
OR rownum = :1 AND ('||V_WHERE||')'
using var1,var2;
There are some options you might consider, although they may require changes, either to how you execute your SQL statement or to your SQL statement itself.
Use DBMS_SQL instead of EXECUTE IMMEDIATE -- DBMS_SQL (see http://docs.oracle.com/cd/B19306_01/appdev.102/b14258/d_sql.htm) is harder to use than EXECUTE IMMEDIATE, but gives you more control over the process -- including the ability (through DBMS_SQL.BIND_VARIABLE and DBMS_SQL.BIND_ARRAY) to bind by name instead of by position.
Use EXECUTE IMMEDIATE with a WITH clause -- You might be able restructure your query to use WITH clause that gathers your bind variables in subquery at the beginning, and then joins to the subquery (instead of referencing the bind variables directly) whenever it needs them. It might look something like this
with your_parameters as
(select :1 as p1, :2 as p2 from dual)
select *
from your_table, your_parameters
where your_table.some_column1 = your_parameters.p1
and your_table.some_column2 <= your_parameters.p1
and your_table.some_column3 = your_parameters.p2
This could affect the performance of your query, but it might be an acceptable compromise.
Don't use dynamic SQL -- Of course, if you don't need dynamic SQL, you don't need to use EXECUTE IMMEDIATE, so the "bind only by position" limitiation does not apply. Are you sure you really need to use dynamic SQL?
EDIT: If you're using dynamic SQL because you have a variable number of OR conditions like you posted in your edit, you might be able to avoid using dynamic SQL by doing one of the following:
If the OR criteria come from a table (or query) -- Join to that table (or query) instead of using a list of OR criteria. For example, if CAT, HAT, and MAT are listed in a column named YOUR_CRITERIA in a table named YOUR_CRITERIA_TABLE you might add YOUR_CRITERIA_TABLE to the FROM clause and replace the OBJECT_NAME LIKE '%CAT% OR OBJECT_NAME LIKE '%MAT% OR OBJECT_NAME LIKE '%HAT% OR OBJECT_NAME LIKE '%MAT% in the WHERE clause with something like OBJECT_NAME LIKE '%' || YOUR_CRITERIA_TABLE.YOUR_CRITERIA || '%'.
Otherwise, you might put the criteria in a global temporary table -- If your criteria don't come from a table (or query), you could (once, at design time, not at run time) create a global temporary table to hold them, and then at run time, insert the criteria into the global temporary table and then join to it as described in item 1.
Or, you might put the criteria in an nested table -- This is like item 2, except uses a nested table (one created using CREATE TYPE...IS TABLE OF) instead of a global temporary table. You could create or own nested table type, or use a built-in one like SYS.ODCIVARCHAR2LIST. In PL/SQL, you would populate an variable of this type, and then use it like a "real" table like in item 1.
An example of item 3 might look something like:
DECLARE
tblCriteria SYS.ODCIVARCHAR2LIST;
BEGIN
tblCriteria := SYS.ODCIVARCHAR2LIST();
-- In "real" code you might populate the nested table in a loop.
-- This example populates it explicitly so that it will compile. For the
-- purpose of the example, we could have populated the nested table in
-- a single statement:
-- tblCriteria := SYS.ODCIVARCHAR2LIST('CAT', 'HAT', 'MAT');
tblCriteria.EXTEND(1);
tblCriteria(tblCriteria.LAST) := 'CAT';
tblCriteria.EXTEND(1);
tblCriteria(tblCriteria.LAST) := 'HAT';
tblCriteria.EXTEND(1);
tblCriteria(tblCriteria.LAST) := 'MAT';
FOR rec IN
(
SELECT
USER_OBJECTS.*
FROM
USER_OBJECTS,
TABLE(tblCriteria) YOUR_NESTED_TABLE
WHERE
USER_OBJECTS.OBJECT_NAME LIKE '%' || YOUR_NESTED_TABLE.COLUMN_VALUE || '%'
)
LOOP
-- Do something. For example, print out the object name.
DBMS_OUTPUT.PUT_LINE(rec.OBJECT_NAME);
END LOOP;
END;
No, unfortunately, the bind variables for EXECUTE IMMEDIATE must be provided in the same order they appear in the statement, and the bind variable names are ignored. So you'll just have to have :1, :2 and :3 in your statement.
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;