I am very new to Oracle 11g and am trying to generate a large string by appending text for each column in a select statement and using a cursor to store the results. However I want the last statement to not have a union all included. The final result I want to build large string of each row generated or simply execute the result if possible.
Note: column1 has a list of schemas that I am interested in.
select 'select * from ' || column1 || '.' || column2 || ' union all ' from mytable
This is where column1 is the schema, column2 is the table name.
What is the simplest way to generate the final string without using rtrim to remove the last string. And is there a simple way to append all these rows together in the string automatically?
The final goal is to actually just execute the union into a resulting cursor.
If you're querying in a loop anyway I wouldn't try to construct the string as part of the select at all; I'd do it all within the loop. Something like (untested):
declare
str varchar2(32768);
begin
for rec in (select column1, column2, rownum as rn from mytable)
loop
if rec.rn > 1 then
str := str || ' union all ';
end if;
str := str || 'select * from "' || rec.column[ || '"."' || rec.column2 ||'"';
end loop;
-- do something with str e.g. display to verify the syntax
-- before using in a cursor
dbms_output.put_line(str);
end;
Rather than adding union all to the end of every row except the last one,the rn check means it's added to the start of every row except the first one, which is easier to detect.
I've also wrapped the schema and table names in double quotes, just in case you have to deal with any quoted identifiers. But if your stored values don't match the case of the owners and table names in all_tables this will cause a problem rather than solve it.
Related
I have a string that contains ID numbers, something like this: „1;3;5;6;7;“
I want to select all rows in an SQLite table that have an ID which is contained in that string.
One select statement that gives me the rows 1,3,5,6 and 7.
Any idea how to do this?
You can do it with LIKE operator:
select * from tablename
where ';' || '1;3;5;6;7' || ';' like '%;' || id || ';%'
You can use the SQLite instr core function
SELECT * FROM your_table WHERE instr(';'||'1;3;5;6;7;',';'||id||';');
preceding the list with ; and wrapping the id in ;'s ensures that only the specific values are extracted (e.g. so that 1 doesn't get 11 111 etc)
I got assigned the following task.
Assume we have a table A structured with an id column and a date column.
Write a procedure in PL/SQL that: takes as parameters the table name (in our case A) and a date D, creates a backup table named A_bck containing only the records of A with dates < D and removes from the table A all the records inserted in A_bck.
Here there is my code.
Unluckily I get this error:
Error report -
ORA-00904: "MAY": invalid identifier
ORA-06512: at line 41
ORA-06512: at line 80
00904. 00000 - "%s: invalid identifier"
If I try to achieve the same result using a where condition on the id column instead that on the date one, I have no problems.
Where is the mistake? Am I implementing it completely in the wrong way?
The problem you have is that as you're executing dynamic sql you're query is built up as a string. Oracle does not know that the date you've given is actually a date, it is simply being treated as part of the string. To solve this you should be able to do the following:
my_query := 'CREATE TABLE ' || table_name_backup || ' AS (SELECT * FROM ' || table_name || ' WHERE table_date < to_date(''' || backup_date || '''))';
This should sort out your issue for you. As a side note, you will probably want to change your "table_exists" query, as table names are all stored in upper case, e.g.
SELECT COUNT(*) INTO table_exists FROM USER_TABLES WHERE TABLE_NAME = upper(my_table);
Edit: Further explanation following comment
To explain why you don't have the above problem when using integers, it is important to remember that using execute immediate simply executes the given string as an SQL query.
For example:
declare
x INTEGER := 1;
i integer;
my_query VARCHAR2(256);
begin
my_query := 'select 1 from dual where 1 = ' || x;
EXECUTE IMMEDIATE my_query INTO i;
end;
my_query in the above example would be executed as:
select 1 from dual where 1 = 1
which is perfectly valid sql. In your example however, you were ending up with something like this:
CREATE TABLE abaco_bck AS (SELECT * FROM abaco WHERE table_date < 27-MAY-17)
As it isn't wrapped in quotes, or explicitly converted to a date, the SQL engine is trying to subtract "MAY" from 27, but it doesn't know what "MAY" is.
One other thing to mention, is that for some operations you could use bind variables instead of quotes (although you can't for DDL) e.g.
declare
lToday DATE := SYSDATE;
i INTEGER;
my_query VARCHAR2(256);
begin
my_query := 'select 1 from dual where sysdate = :1';
EXECUTE IMMEDIATE my_query INTO i USING lToday;
end;
I have an Oracle table called: col_mapping where a column in this table has the column values of columns from another table.
Example data of table: col_mapping
ID DESCR COL_VALS
------------------------------
1 LABEL COL_1
2 NAME_ADDR COL_2:COL_3
3 SALARY COL4
Based on the above table, I now would like to go through each record in col_mapping and use the COL_VALS as part of my
select COL_VALS from other_tab
obviously, where there is more than one value like COL_2:COL_3, need to replace the ':' with a ','
SELECT COL_1 from other_tab;
SELECT COL_2,COL_3 from other_tab;
SELECT COL_4 from other_tab;
You can generate and execute insert statements based on the col_vals value using dynamic SQL, inside a cursor loop over the col_mappings rows:
begin
for r in (select replace(col_vals, ':', ',') as cols from col_mapping) loop
dbms_output.put_line('insert into staging_tab(' || r.cols || ')'
|| ' select ' || r.cols || ' from other_tab');
execute immediate 'insert into staging_tab(' || r.cols || ')'
|| ' select ' || r.cols || ' from other_tab';
end loop;
end;
/
The cursor just gets the cols_val value, replacing colon with comma. The generated insert uses that modified cols_val as both the insert column list and the select list - since you said the staging table will match the other_tab structure.
The dbms_output line is just so you can see the generated statements - it ins't necessary for the code to run, and you'll need to set serveroutput on or equivalent to see it anyway. With that enabled, running that block using your example mapping data shows:
PL/SQL procedure successfully completed.
insert into staging_tab(COL_1) select COL_1 from other_tab
insert into staging_tab(COL_2,COL_3) select COL_2,COL_3 from other_tab
insert into staging_tab(COL4) select COL4 from other_tab
What you'll end up with is the data from each row in other_tab spread across multiple rows in staging_tab, with lots of null values. Hopefully that's what you intended.
This procedure is getting following error.
CREATE OR REPLACE PROCEDURE SAMPLE
IS
BEGIN
EXECUTE IMMEDIATE
'CREATE TABLE COLUMN_NAMES AS (
SELECT LISTAGG(COLUMN_NAME, ',') WITHIN GROUP (ORDER BY COLUMN_NAME) AS STUDENTS
FROM
(SELECT DISTINCT COLUMN_NAME
FROM BW_COLUMN_ROW_CELL_JOIN)
)';
END;
/
gives:
PLS-00103: Encountered the symbol "," when expecting one of the following:
* & = - + ; < / > at in is mod remainder not rem return
returning <an exponent (**)> <> or != or ~= >= <= <> and or
like like2 like4 likec between into using || multiset bulk member submultiset
Can any one say what is wrong in this?
Thanks.
Another way (in Oracle 10g and later) is to use the alternative string literal notation - this means you don't need to worry about correctly escaping all the single quotes in the string, e.g. q'{my string's got embedded quotes}':
CREATE OR REPLACE PROCEDURE SAMPLE
IS
BEGIN
EXECUTE IMMEDIATE q'[
CREATE TABLE COLUMN_NAMES AS (
SELECT LISTAGG(COLUMN_NAME, ',') WITHIN GROUP (ORDER BY COLUMN_NAME) AS STUDENTS
FROM
(SELECT DISTINCT COLUMN_NAME
FROM BW_COLUMN_ROW_CELL_JOIN)
)]';
END;
/
The problem I think is you have single quotes within single quotes. I cant test this at the moment, but I'd suggest you try the following (note the inner quotes are double quotes '', which escapes them:
CREATE OR REPLACE PROCEDURE SAMPLE
IS
BEGIN
EXECUTE IMMEDIATE 'CREATE TABLE COLUMN_NAMES AS ( SELECT LISTAGG(COLUMN_NAME, '','') WITHIN GROUP (ORDER BY COLUMN_NAME) AS STUDENTS FROM (SELECT DISTINCT COLUMN_NAME FROM BW_COLUMN_ROW_CELL_JOIN) )';
END;
/
I'd also try the create table part of the code standalone first just to make sure its valid before wrapping it in a proc.
You can't use single quotes directly in select statement of Execute Immediate it need to be coded using CHR(39)
CREATE OR REPLACE PROCEDURE SAMPLE
IS
BEGIN
EXECUTE IMMEDIATE
'CREATE TABLE COLUMN_NAMES AS (
SELECT LISTAGG(COLUMN_NAME,'||chr(39)||','||chr(39)||') WITHIN GROUP (ORDER BY COLUMN_NAME) AS STUDENTS
FROM
(SELECT DISTINCT COLUMN_NAME FROM BW_COLUMN_ROW_CELL_JOIN))';
END;
I am having trouble getting a block of pl/sql code to work. In the top of my procedure I get some data from my oracle apex application on what checkboxes are checked. Because the report that contains the checkboxes is generated dynamically I have to loop through the
APEX_APPLICATION.G_F01
list and generate a comma separated string which looks like this
v_list VARCHAR2(255) := (1,3,5,9,10);
I want to then query on that list later and place the v_list on an IN clause like so
SELECT * FROM users
WHERE user_id IN (v_list);
This of course throws an error. My question is what can I convert the v_list to in order to be able to insert it into a IN clause in a query within a pl/sql procedure?
If users is small and user_id doesn't contain commas, you could use:
SELECT * FROM users WHERE ',' || v_list || ',' LIKE '%,'||user_id||',%'
This query is not optimal though because it can't use indexes on user_id.
I advise you to use a pipelined function that returns a table of NUMBER that you can query directly. For example:
CREATE TYPE tab_number IS TABLE OF NUMBER;
/
CREATE OR REPLACE FUNCTION string_to_table_num(p VARCHAR2)
RETURN tab_number
PIPELINED IS
BEGIN
FOR cc IN (SELECT rtrim(regexp_substr(str, '[^,]*,', 1, level), ',') res
FROM (SELECT p || ',' str FROM dual)
CONNECT BY level <= length(str)
- length(replace(str, ',', ''))) LOOP
PIPE ROW(cc.res);
END LOOP;
END;
/
You would then be able to build queries such as:
SELECT *
FROM users
WHERE user_id IN (SELECT *
FROM TABLE(string_to_table_num('1,2,3,4,5'));
You can use XMLTABLE as follows
SELECT * FROM users
WHERE user_id IN (SELECT to_number(column_value) FROM XMLTABLE(v_list));
I have tried to find a solution for that too but never succeeded. You can build the query as a string and then run EXECUTE IMMEDIATE, see http://docs.oracle.com/cd/B19306_01/appdev.102/b14261/dynamic.htm#i14500.
That said, it just occurred to me that the argument of an IN clause can be a sub-select:
SELECT * FROM users
WHERE user_id IN (SELECT something FROM somewhere)
so, is it possible to expose the checkbox values as a stored function? Then you might be able to do something like
SELECT * FROM users
WHERE user_id IN (SELECT my_package.checkbox_func FROM dual)
Personally, i like this approach:
with t as (select 'a,b,c,d,e' str from dual)
--
select val
from t, xmltable('/root/e/text()'
passing xmltype('<root><e>' || replace(t.str,',','</e><e>')|| '</e></root>')
columns val varchar2(10) path '/'
)
Which can be found among other examples in Thread: Split Comma Delimited String Oracle
If you feel like swamping in even more options, visit the OTN plsql forums.