I'm working with an oracle database and what I basically need to do is to count the number of NULL fields per column in a certain table.
something like that:
DECLARE
BlankCount number(20);
i number(2) := 1;
BEGIN
loop that would take each column individualy and exit after the last one
SELECT COUNT(*) INTO BlankCount FROM name_of_my_table
DBMS_OUTPUT.PUT_LINE('Column '||i||' has '||BlankCount||' empty cells');
i := i + 1;
END LOOP;
END;
I just couldn't find anything that would do the loop part.
It would also be nice if instead of just numbering them (with the i) I could display the column name (but that is not very important).
Thank you!
Something like this:
declare
mytable varchar(32) := 'MY_TABLE';
cursor s1 (mytable varchar2) is
select column_name
from user_tab_columns
where table_name = mytable
and nullable = 'Y';
mycolumn varchar2(32);
query_str varchar2(100);
mycount number;
begin
open s1 (mytable);
loop
fetch s1 into mycolumn;
exit when s1%NOTFOUND;
query_str := 'select count(*) from ' || mytable || ' where ' || mycolumn || ' is null';
execute immediate query_str into mycount;
dbms_output.put_line('Column ' || mycolumn || ' has ' || mycount || ' null values');
end loop;
end;
Try using cursor approach and Dynamic SQL as mentioned in this thread: How to loop through columns in an oracle pl/sql cursor
HTH.
Related
I am trying hard dynamic PL/SQL thing here.
I don't manage to fetch a column dynamic Query.
I am iterating on the name of the column to concatenate a full query in order to be executed on another table.
sql_req := 'select ';
for c in (SELECT name_col from TAB_LISTCOL)
loop
sql_req := sql_req || 'sum(' || c.name_col || '),';
end loop;
sql_req := sql_req || ' from ANOTHER_TAB ';
And when i try to execute it with EXECUTE IMMEDIATE or cursors or INTO/BULK COLLECT thing or just to fetch, i don't manage to iterate on the result.
I tried a lot.
Can you help me plz ? Or maybe it is not possible ?
ps : i know the coma is wrong but my code is more complexe than this : i didn't want to put more things
If you only want to get string columns, you can use listagg
select listagg(name_col, ',') WITHIN GROUP (ORDER BY null) from TAB_LISTCOL
Please see if this helps
In the absence of actual table structure and requirement, I'm creating dummy tables and query to illustrate an example:
SQL> create table another_tab
as
select 10 dummy_value1, 100 dummy_value2, 1000 dummy_value3 from dual union all
select 11 dummy_value1, 101 dummy_value2, 1001 dummy_value3 from dual union all
select 12 dummy_value1, 102 dummy_value2, 1003 dummy_value3 from dual
;
Table created.
SQL> create table tab_listcol
as select column_name from dba_tab_cols where table_name = 'ANOTHER_TAB'
;
Table created.
To reduce complexity in the final block, I'm defining a function to generate the dynamic sql query. This is based on your example and will need changes according to your actual requirement.
SQL> create or replace function gen_col_based_query
return varchar2
as
l_query varchar2(4000);
begin
l_query := 'select ';
for cols in ( select column_name cname from tab_listcol )
loop
l_query := l_query || 'sum(' || cols.cname || '), ' ;
end loop;
l_query := rtrim(l_query,', ') || ' from another_tab';
return l_query;
end;
/
Function created.
Sample output from the function will be as follows
SQL> select gen_col_based_query as query from dual;
QUERY
--------------------------------------------------------------------------------
select sum(DUMMY_VALUE1), sum(DUMMY_VALUE2), sum(DUMMY_VALUE3) from another_tab
Below is a sample block for executing a dynamic cursor using DBMS_SQL. For your ease of understanding, I've added comments wherever possible. More info here.
SQL> set serveroutput on size unlimited
SQL> declare
sql_stmt clob;
src_cur sys_refcursor;
curid number;
desctab dbms_sql.desc_tab; -- collection type
colcnt number;
namevar varchar2 (50);
numvar number;
datevar date;
l_header varchar2 (4000);
l_out_rows varchar2 (4000);
begin
/* Generate dynamic sql from the function defined earlier */
select gen_col_based_query into sql_stmt from dual;
/* Open cursor variable for this dynamic sql */
open src_cur for sql_stmt;
/* To fetch the data, however, you cannot use the cursor variable, since the number of elements fetched is unknown at complile time.
Therefore you use DBMS_SQL.TO_CURSOR_NUMBER to convert a REF CURSOR variable to a SQL cursor number which you can then pass to DBMS_SQL subprograms
*/
curid := dbms_sql.to_cursor_number (src_cur);
/* Use DBMS_SQL.DESCRIBE_COLUMNS to describe columns of your dynamic cursor, returning information about each column in an associative array of records viz., desctab. The no. of columns is returned in colcnt variable.
*/
dbms_sql.describe_columns (curid, colcnt, desctab);
/* Define columns at runtime based on the data type (number, date or varchar2 - you may add to the list)
*/
for indx in 1 .. colcnt
loop
if desctab (indx).col_type = 2 -- number data type
then
dbms_sql.define_column (curid, indx, numvar);
elsif desctab (indx).col_type = 12 -- date data type
then
dbms_sql.define_column (curid, indx, datevar);
else -- assuming string
dbms_sql.define_column (curid, indx, namevar, 100);
end if;
end loop;
/* Print header row */
for i in 1 .. desctab.count loop
l_header := l_header || ' | ' || rpad(desctab(i).col_name,20);
end loop;
l_header := l_header || ' | ' ;
dbms_output.put_line(l_header);
/* Loop to retrieve each row of data identified by the dynamic cursor and print output rows
*/
while dbms_sql.fetch_rows (curid) > 0
loop
for indx in 1 .. colcnt
loop
if (desctab (indx).col_type = 2) -- number data type
then
dbms_sql.column_value (curid, indx, numvar);
l_out_rows := l_out_rows || ' | ' || rpad(numvar,20);
elsif (desctab (indx).col_type = 12) -- date data type
then
dbms_sql.column_value (curid, indx, datevar);
l_out_rows := l_out_rows || ' | ' || rpad(datevar,20);
elsif (desctab (indx).col_type = 1) -- varchar2 data type
then
dbms_sql.column_value (curid, indx, namevar);
l_out_rows := l_out_rows || ' | ' || rpad(namevar,20);
end if;
end loop;
l_out_rows := l_out_rows || ' | ' ;
dbms_output.put_line(l_out_rows);
end loop;
dbms_sql.close_cursor (curid);
end;
/
PL/SQL procedure successfully completed.
Output
| SUM(DUMMY_VALUE1) | SUM(DUMMY_VALUE2) | SUM(DUMMY_VALUE3) |
| 33 | 303 | 3004 |
You have to use EXECUTE IMMEDIATE with BULK COLLECT
Below is an example of the same. For more information refer this link
DECLARE
TYPE name_salary_rt IS RECORD (
name VARCHAR2 (1000),
salary NUMBER
);
TYPE name_salary_aat IS TABLE OF name_salary_rt
INDEX BY PLS_INTEGER;
l_employees name_salary_aat;
BEGIN
EXECUTE IMMEDIATE
q'[select first_name || ' ' || last_name, salary
from hr.employees
order by salary desc]'
BULK COLLECT INTO l_employees;
FOR indx IN 1 .. l_employees.COUNT
LOOP
DBMS_OUTPUT.put_line (l_employees (indx).name);
END LOOP;
END;
If I understand correctly, you want to create a query and execute it and return the result to another function or some calling app. As the resulting query's columns are note before-known, I'd return a ref cursor in this case:
create function get_sums return sys_refcur as
declare
my_cursor sys_refcursor;
v_query varchar2(32757);
begin
select
'select ' ||
listagg('sum(' || name_col || ')', ', ') within group (order by name_col) ||
' from another_tab'
into v_query
from tab_listcol;
open my_cursor for v_query;
return v_query;
end get_sums;
I am trying to create an Oracle procedure to delete records from multiple tables of an owner based upon a distinct count condition:
Firstly I am trying to obtain the tables for which I want to delete those records with this query:
SELECT * FROM ALL_TABLES WHERE OWNER = 'Lorik' AND TABLE_NAME LIKE 'UT_%';
This results in a total of 300 tables, now all of those tables have a column named: DATE_INC
I am trying to delete records from all of the tables if this COUNT(DISTINCT DATE_INC) > 5.
Assuming that one of those 300 tables is named UT_NAMES:
SELECT COUNT(DISTINCT DATE_INC) FROM Lorik.UT_NAMES;
So if the count exceeds 5, then I want to delete the records with the minimum date:
DELETE MIN(DATE_INC) FROM Lorik.UT_NAMES;
Can someone please link these steps together so I can loop through each table of that owner and obtain the distinct date count and delete records based upon the above cited condition.
Thanks in advance!
You can use 'EXECUTE IMMEDIATE' in PL/SQL to accomplish your goal:
DECLARE
strTable VARCHAR2(32767);
nCount NUMBER;
BEGIN
FOR aRow IN (SELECT *
FROM ALL_TABLES
WHERE OWNER = 'Lorik' AND
TABLE_NAME LIKE 'UT_%')
LOOP
strTable := aRow.OWNER || '.' || aRow.TABLE_NAME;
EXECUTE IMMEDIATE 'SELECT COUNT(DISTINCT DATE_INC) FROM ' || strTable
INTO nCount;
IF nCount > 5 THEN
EXECUTE IMMEDIATE 'DELETE FROM ' || strTable ||
' WHERE DATE_INC = (SELECT MIN(DATE_INC) ' ||
'FROM ' || strTable || ')';
END IF;
END LOOP;
END;
Not tested on animals - you'll be first! :-)
As pointed out by #Andrew this seems to be very basic processes.
Declare some variables.
Open a cursor.
Use dynamic sql to count
Use dynamic sql to delete
Add some log information
_
declare
v_cnt number;
v_sql varchar2(1000);
begin
for cur in (SELECT * FROM ALL_TABLES WHERE OWNER = 'HR' AND TABLE_NAME LIKE 'E%')
loop
v_sql := 'select count(distinct department_id||''date_inc'') from '||cur.owner||'. '||cur.table_name;
execute immediate v_sql into v_cnt;
dbms_output.put_line (cur.table_name || ': ' || v_cnt);
if v_cnt > 5 then
v_sql := 'delete from '||cur.owner||'. '||cur.table_name || ' where date_inc = (select min (date_inc) from ' ||cur.owner||'. '||cur.table_name || ')';
dbms_output.put_line (v_sql);
-- execute immediate v_sql;
end if;
end loop;
rollback;
-- commit;
end;
A little bit simpler dynamic SQL for deleting rows, as it uses a local variable:
declare
l_cnt number; -- counter variable
l_min_date date; -- MIN(date_inc)
begin
for cur_t in (select table_name from all_tables
where owner = 'Lorik' -- are you sure it is not uppercase, LORIK?
and table_name like 'UT%' -- underline is wildcard character so you don't need it
)
loop
execute immediate 'select count(distinct date_inc), min(date_inc) from ' ||
cur_t.table_name into l_cnt, l_min_date;
if l_cnt > 5 then
execute immediate 'delete from ' || cur_t.table_name ||
' where date_inc = ' || l_min_date_inc;
end if;
end loop;
end;
/
Is there any way i can verify if my inserts were successful into my secondary table and then deleting from my original table those rows, without using a trigger.
SO i have this query: has 2 dynamic tables n_tab and n_tab2
testes:= 'INSERT all into ' || n_tab2 || ' SELECT * FROM ' || n_tab || ' where criado_em< ' || SYSDATE;
EXECUTE IMMEDIATE testes;
after this insert i would like to verify if all the rows were inserted and after that
stmt_del:= 'DELETE FROM ' || n_tab || ' WHERE EXISTS (SELECT 1
FROM ' || n_tab2 || ' WHERE ' 'need to find a way to associate the pk and fk dinamically'
EXECUTE IMMEDIATE testes;
Thank you in advance.
if not find any way , here is way using SQL%ROWCOUNT
DECLARE
stmt varchar2(100);
mycolumn NUMBER := 100 ;
BEGIN
stmt := 'insert into mytable values('||mycolumn||')';
execute immediate stmt;
dbms_output.put_line('value '||SQL%ROWCOUNT);
IF SQL%ROWCOUNT > 1 THEN
stmt_del:= 'delete from mytable where condition';
EXECUTE IMMEDIATE testes;
END IF;
END;
I need to verify converted data, distinct values and records counts. I would like to write statements so that I can enter a table name, then retrieve it's columns and use them in a query to get its distinct values (the actual values, not just a count of how many distinct) and their count.
I think I need to a CURSOR or CURSOR FOR LOOP and create something like this:
declare
cursor field_name
is
select COLUMN_NAME
from user_tab_cols
where table_name='TABLE1'
c_field_name field_name%ROWTYPE;
BEGIN
OPEN field_name
loop
fetch field_name INTO c_field_name;
exit when field_name%NOTFOUND;
end loop;
CLOSE field_name;
end;
Then run a query using that above in something like
select field_name, count(*)
from table1
group by field_name
Do I need to create 2 loop statements? I've not yet created one and can't quite get the context to get my results so far.
BEGIN
FOR myrow in (select field_name, count(*) as "count" from table1 group by field_name)
loop
dbms_output.put_line(myrow.field_name);
dbms_output.put_line(myrow.count);
end loop;
end;
Considering you will be giving the table name as parameter below code will print all the values of all the columns one by one along with the count of the values
create or replace PROCEDURE PR_PREP(
P_TABLE_NAME IN VARCHAR2)
IS
CURSOR CUR_COLUMNS (PA_TABLE_NAME VARCHAR2)
IS
SELECT COLUMN_NAME FROM ALL_TAB_COLUMNS WHERE TABLE_NAME = PA_TABLE_NAME;
COL_NAMES CUR_COLUMNS%ROWTYPE;
TYPE TYP_RECORD
IS
RECORD
(
FIELD_NAME VARCHAR2(255),
CNT INT);
TYPE TYP_OP_TABLE
IS
TABLE OF TYP_RECORD;
OP_TABLE TYP_OP_TABLE;
I INT;
V_SQL VARCHAR2(2000);
BEGIN
FOR COL_NAMES IN CUR_COLUMNS(P_TABLE_NAME)
LOOP
V_SQL := 'SELECT ' || COL_NAMES.COLUMN_NAME || ' AS FIELD_NAME ,
COUNT(*) AS CNT FROM ' ||
P_TABLE_NAME || ' GROUP BY ' || COL_NAMES.COLUMN_NAME ;
-- DBMS_OUTPUT.PUT_LINE (V_SQL);
EXECUTE IMMEDIATE V_SQL BULK COLLECT INTO OP_TABLE;
dbms_output.put_line('columna name = ' ||COL_NAMES.COLUMN_NAME);
FOR I IN OP_TABLE.FIRST .. OP_TABLE.LAST
LOOP
DBMS_OUTPUT.PUT_LINE('FIELD VALUE '||OP_TABLE(I).FIELD_NAME || ' COUNT = ' || OP_TABLE(I).CNT);
END LOOP;
DBMS_OUTPUT.PUT_LINE('ONE FILED ENDED , NEXT STARTED');
END LOOP;
END;
I try to search a number from multiple columns (datatype number), but get ORA-01722: invalid number error.
My Query:
SELECT *
FROM CAMPAIGN
WHERE 1481125 IN (select column_name
from all_tab_columns
where table_name = 'CAMPAIGN'
AND data_type = 'NUMBER');
What is wrong with it?
You are comparing your number 1481125 with the names of the each column, not the values of each column in your table.
To go from a column's name (from dba_tab_columns) to the values in that column, you need to use some form of dynamic SQL. Here's a relatively simple example:
DECLARE
-- Since I don't have your CAMPAIGN table or data, I'm using DBA_OBJECTS in it's place.
l_table_name VARCHAR2 (30) := 'DBA_OBJECTS';
l_search_number NUMBER := 20; -- 1481125 in your example
l_record dba_objects%ROWTYPE;
l_sql VARCHAR2 (32000);
l_column_number NUMBER := 0;
l_cur SYS_REFCURSOR;
BEGIN
-- First: build dynamic SQL statement of the form:
-- SELECT * FROM table_name WHERE
-- ( ( col_name_a = 20 ) OR ( col_name_b = 20 ) OR ... )
l_sql := 'SELECT * FROM dba_objects WHERE ( ';
FOR r_number_column IN (SELECT column_name
FROM dba_tab_columns
WHERE table_name = l_table_name
AND data_type = 'NUMBER'
ORDER BY column_id) LOOP
IF l_column_number > 0 THEN
l_sql := l_sql || ' OR ';
END IF;
l_column_number := l_column_number + 1;
l_sql := l_sql || '(' || r_number_column.column_name || ' = ' || l_search_number || ')';
END LOOP;
IF l_column_number = 0 THEN
-- No number columns in table, so there should be no matches
l_sql := l_sql || ' 1=0';
END IF;
l_sql := l_sql || ')';
DBMS_OUTPUT.put_line (l_sql);
OPEN l_cur FOR l_sql;
LOOP
FETCH l_cur INTO l_record;
EXIT WHEN l_cur%NOTFOUND;
DBMS_OUTPUT.put_line ('Object Name ' || l_record.object_name || ' has search number ' || l_search_number);
END LOOP;
END;
Your query is:
SELECT * FROM CAMPAIGN WHERE 1481125 IN
(select column_name from all_tab_columns where table_name = 'CAMPAIGN' AND data_type='NUMBER')
Breaking that down we have:
SELECT * FROM CAMPAIGN WHERE 1481125 IN (<a set of numbers>)
and the subquery:
select column_name from all_tab_columns
where table_name = 'CAMPAIGN'
AND data_type='NUMBER'
That subquery is going to return a list of column names e.g.
CAMPAIGN_COUNT
CAMPAIGN_ID
CAMPAIGN_NUMBER_OF_SOMETHINGS
Your query is thus equivalent to:
SELECT * FROM CAMPAIGN WHERE 1481125 IN
('CAMPAIGN_COUNT', 'CAMPAIGN_ID', 'CAMPAIGN_NUMBER_OF_SOMETHINGS')
You can see why you would get the ORA-01722 error there?
You would need to write dynamic SQL to achieve your aim.