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
Related
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 am trying to write a stored procedure in Oracle in which I am passing string value in myString whose value is like ('xxx','yyy') as varchar and returning a cursor. My procedure looks like as below:
create or replace getName (in_myString in varchar, Name_list out refcursor) IS
Begin
Open cursor for
Select Colunm1 from table where columnName in (in_MyString);
But is not returning any records but I am trying to run the query alone it is returning the records. Please can anyone help me?
Assuming your input value for the parameter is like this in_myString := 'xxx,yyy'; we can use SQL regular expression functions to split your values based on comma and pass the result list to IN clause.
create or relace getName( in_myString in varchar, Name_list out refcursor) IS
Begin
Open cursor for
Select Colunm1 from table where columnName in
(select regexp_substr(in_myString,'[^,]+', 1, level) from dual
connect by regexp_substr(in_myString, '[^,]+', 1, level) is not null);
More info on regular expression can be found here.
I have 2 tables with same set Column Name (52+ coulmns) . I need to write an Oracle function to compare whether any records get changed between these columns. EMP_ID is the primary Key
I'm trying to use the below function, but it is giving me incorrect result,
I'm calling the funcaiton like this:
get_data_change (emp_id, 'DEPT_NAME');
get_data_change (emp_id, 'PHONE_NUMBER');
Function I have created:
CREATE OR REPLACE function get_data_change (
in_emp_id varchar2, in_Column_Name varchar2)
return char is
v_data_changed char;
begin
select eid, in_Column_Name
into v_table1_eid, v_table1_Column_Value
from table 1
where eid=in_emp_id;
Select eid, in_Column_Name
into v_table2_eid, v_table2_Column_Value
from table 2
where eid = in_emp_id;
if ( v_table2_Column_Value != v_table1_Column_Value)
then
v_data_changed := 'Y'
else
v_data_changed :='N'
endif
return v_data_changed
end
end get_data_change;
in_Column_Name is a string variable to which you are assigning a literal string value such as 'DEPT_NAME'.
Therefore, your queries are interpreting this as a literal string value and returning the same thing into v_table1_Column_Value.
To do what you expect you need to use Dynamic SQL, something like:
EXECUTE IMMEDIATE 'select eid, ' || in_Column_Name
|| ' from table1 where eid=:P_emp_id'
into v_table1_eid, v_table1_Column_Value
using in_emp_id;
You need to be aware of the possibility of SQL Injection here - i.e. the value of in_Column_Name cannot be supplied by end-users.
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;