For example I have a table with data:
Column1 Column2 Column3 ... Column1xx
1 a 10 x
2 b 20 y
3 c 30 z
What SQL query would get me only the last column?
Column1xx
x
y
z
Note: Column Name and Index of the last column is unknown
Fill your_table_schema and your_table_name. Originated from the post https://stackoverflow.com/a/38993544/18396231
SELECT COLUMN_NAME, ORDINAL_POSITION
FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = '{your_table_schema}'
AND TABLE_NAME ='{your_table_name}'
ORDER BY ORDINAL_POSITION DESC
LIMIT 1;
create so test data:
CREATE TABLE test.test.testo(aa number, bb number, cc number);
INSERT INTO test.test.testo values (1,10,100),(2,20,200),(3,30,300);
use tasozgurcem11 SQL to show we can get the column name:
SELECT COLUMN_NAME
FROM test.information_schema.COLUMNS
WHERE TABLE_SCHEMA = 'TEST'
AND TABLE_NAME ='TESTO'
ORDER BY ORDINAL_POSITION DESC
LIMIT 1;
and the put that into Snowflake Scripting to having it run dynamically:
DECLARE
query STRING;
col_name STRING;
res RESULTSET;
BEGIN
LET _database := 'TEST';
LET _table := 'TESTO';
LET _schema := 'TEST';
SELECT COLUMN_NAME INTO :col_name
FROM test.information_schema.COLUMNS
WHERE TABLE_SCHEMA = :_schema
AND TABLE_NAME = :_table
ORDER BY ORDINAL_POSITION DESC
LIMIT 1;
QUERY := 'SELECT '|| :col_name ||' FROM '|| _database ||'.'|| _schema ||'.'|| _table ||';';
res := (EXECUTE IMMEDIATE :QUERY);
return table(res);
END;
gives:
CC
100
200
300
this may help you where a function returns the last column name.
create or replace TABLE TEST_TABLE (
ID NUMBER(38,0),
C1 NUMBER(38,0),
C2 VARCHAR(16777216) MASKING POLICY TEST_HK.PUBLIC.MASK_DATA,
C3 DATE
);
CREATE OR REPLACE function LST_COLUMN(tab_nam varchar)
RETURNS VARCHAR
AS 'select column_name from information_schema.columns where table_name = tab_nam and ORDINAL_POSITION
= (SELECT max(ORDINAL_POSITION) from information_schema.columns where table_name = tab_nam)';
select LST_COLUMN('TEST_TABLE') from test_table;
Related
postgres 12
I am trying to loop through a table which has schema , table_names and columns
I want to do various things like finding nulls ,row count etc. I failed at the first hurdle trying to update the col records.
table i am using
CREATE TABLE test.table_study (
table_schema text,
table_name text,
column_name text,
records int,
No_Nulls int,
No_Blanks int,
per_pop int
);
I populate the table with some schema names ,tables and columns from information_schema.columns
insert into test.table_study select table_schema, table_name, column_name
from information_schema.columns
where table_schema like '%white'
order by table_schema, table_name, ordinal_position;
I want to populate the rest with a function
function :-
CREATE OR REPLACE PROCEDURE test.insert_data_population()
as $$
declare s record;
declare t record;
declare c record;
BEGIN
FOR s IN SELECT distinct table_schema FROM test.table_study
LOOP
FOR t IN SELECT distinct table_name FROM test.table_study where table_schema = s.table_schema
loop
FOR c IN SELECT column_name FROM test.table_study where table_name = t.table_name
LOOP
execute 'update test.table_study set records = (select count(*) from ' || s.table_schema || '.' || t.table_name || ') where table_study.table_name = '|| t.table_name ||';';
END LOOP;
END LOOP;
END LOOP;
END;
$$
LANGUAGE plpgsql;
I get this error SQL Error [42703]: ERROR: column "age" does not exist. the table age does exist.
when I take out the where clause
execute 'update referralunion.testinsert ti set records = (select count(*) from ' || s.table_schema || '.' || t.table_name || ') ;';
it works, I just cant figure out whats wrong?
Your procedure is structured entirely wrong. What it results in is an attempt to get every column name for every table name in every schema. I would guess results in your column does not exist error. Further is shows procedural thinking. SQL requires think in terms of sets. Below I use basically your query to demonstrate then a revised version which uses a single loop.
-- setup (dropping schema references)
create table table_study (
table_schema text,
table_name text,
column_name text,
records int,
no_nulls int,
no_blanks int,
per_pop int
);
insert into table_study(table_schema, table_name, column_name)
values ('s1','t1','age')
, ('s2','t1','xyz');
-- procedure replacing EXECUTE with Raise Notice.
create or replace procedure insert_data_population()
as $$
declare
s record;
t record;
c record;
line int = 0;
begin
for s in select distinct table_schema from table_study
loop
for t in select distinct table_name from table_study where table_schema = s.table_schema
loop
for c in select column_name from table_study where table_name = t.table_name
loop
line = line+1;
raise notice '%: update table_study set records = (select count(*) from %.% where table_study.table_name = %;'
, line, s.table_schema, t.table_name, c.column_name;
end loop;
end loop;
end loop;
end;
$$
language plpgsql;
Run procedure
do $$
begin
call insert_data_population();
end;
$$;
RESULTS
1: update table_study set records = (select count(*) from s2.t1 where table_study.table_name = age; 2: update table_study set records = (select count(*) from s2.t1 where table_study.table_name = xyz; 3: update table_study set records = (select count(*) from s1.t1 where table_study.table_name = age; 4: update table_study set records = (select count(*) from s1.t1 where table_study.table_name = xyz;
Notice lines 2 and 3. Each references a column name that does not exist in the table. This results from the FOR structure with the same table name in different schema.
Revision for Single Select statement with Single For loop.
create or replace
procedure insert_data_population()
language plpgsql
as $$
declare
s record;
line int = 0;
begin
for s in select distinct table_schema, table_name, column_name from table_study
loop
line = line+1;
raise notice '%: update table_study set records = (select count(*) from %.% where table_study.table_name = %;'
, line, s.table_schema, s.table_name, s.column_name;
end loop;
end;
$$;
do $$
begin
call insert_data_population();
end;
$$;
RESULTS
1: update table_study set records = (select count(*) from s2.t1 where table_study.table_name = xyz;
2: update table_study set records = (select count(*) from s1.t1 where table_study.table_name = age;
Note: In Postgres DECLARE begins a block. It is not necessary to declared each variable. I would actually consider it bad practice. In theory it could require an end for each declare as each could be considered a nested block. Fortunately Postgres does not require this.
I am using Oracle sqlplus and am trying to use the result being selected from the codes below and select the column again from Table_1
SELECT *
FROM
(
SELECT Column_Name
FROM All_Tab_columns
WHERE Table_Name=UPPER('Table_1')
)
INTERSECT
(
SELECT Column_Name
FROM All_Tab_columns
WHERE Table_Name=UPPER('Table_2')
);
How can I perform something like that:
SELECT <Columns_That_Intersected>
FROM Table_1;
Is it possible to store the Columns_That_Intersected in a variable/function/procedure and use it again for other select statement?
Yes, it's possible. Just save the aggregated result of the query in a substitution variable. Something like this:
create table items1 as
select rownum id, 'me '||rownum name, 1 dummy
from xmlTable ('1 to 3');
create table items2 as select id, name from items1;
set verify off
col Columns_That_Intersected new_value Columns_That_Intersected noprint
select listagg (column_name, ',') within group (order by null) Columns_That_Intersected
from (
select column_name
from All_Tab_Columns
where Table_Name=UPPER('items1')
intersect
select column_name
from All_Tab_columns
where Table_Name=UPPER('items2')
);
prompt Columns_That_Intersected=&Columns_That_Intersected
select &Columns_That_Intersected
from items1;
Output:
Columns_That_Intersected=ID,NAME
ID NAME
---------- -------------------------------------------
1 me 1
2 me 2
3 me 3
About col[umn] command
Just to fetch the column names which exists in both the table table1 and table2, you can use below query:
SELECT Column_Name
FROM all_tab_columns t1
WHERE table_name = 'Table1'
AND EXISTS (SELECT 1
FROM all_tab_columns t2
WHERE table_name = 'Table2'
AND t2.Column_Name = t1.Column_Name);
Then to fetch these column values from Table1, you can use below PL/SQL construct:
DECLARE
v_sql_statement VARCHAR2(2000);
v_cols VARCHAR2(2000);
BEGIN
FOR cn IN (SELECT Column_Name
FROM all_tab_columns t1
WHERE table_name = 'Table1'
AND EXISTS (SELECT 1
FROM all_tab_columns t2
WHERE table_name = 'Table2'
AND t2.Column_Name = t1.Column_Name))
LOOP
v_cols := v_cols || ', ' || cn.column_name;
END LOOP;
v_cols := ltrim(v_cols, ',');
v_sql_statement := 'SELECT ' || v_cols || ' FROM Table1';
EXECUTE IMMEDIATE v_sql_statement;
END;
you can, for example, work with a dynamic sql.
The result of your selects can be aggregated to a list using the listagg function
SELECT listagg( Column_Name,',') WITHIN GROUP (ORDER BY 1) cols
FROM
(
SELECT Column_Name
FROM All_Tab_columns
WHERE Table_Name=UPPER('tab1')
INTERSECT
SELECT Column_Name
FROM All_Tab_columns
WHERE Table_Name=UPPER('tab2')
);
As result you get then eg. col1, col2, col3
with the help of this list you can then create a cursor in a plsql block and then loop through it to print out wat you want.
declare
v_cols VARCHAR2(2000);
v_select_string varchar(2000);
csr SYS_REFCURSOR;
v1 VARCHAR2(2000);
BEGIN
SELECT listagg( Column_Name,',') WITHIN GROUP (ORDER BY 1) cols
into v_cols
FROM
(
SELECT Column_Name
FROM All_Tab_columns
WHERE Table_Name=UPPER('tab1')
INTERSECT
SELECT Column_Name
FROM All_Tab_columns
WHERE Table_Name=UPPER('tab2')
);
v_select_string := 'SELECT ' || v_cols ||
' FROM tab1';
OPEN csr FOR v_select_string;
LOOP
FETCH csr INTO v1;
EXIT WHEN csr%NOTFOUND;
DBMS_OUTPUT.PUT_LINE( v1);
END LOOP;
CLOSE csr;
END P1;
I need to 'recreate' over 50 tables (in Oracle) with CREATE AS SELECT statements. However, all this tables will have one column modified using data from another table. Is there a way to achieve this without declaring each column in the SELECT statement?
Something like:
CREATE TABLE table_name_copy AS SELECT *, (SELECT col_name FROM other_table WHERE other_table.col_id = table_name.col_id) AS col_name FROM table_name`
Basically on all tables I have a column which needs to be replaced with the data in the other_table column.
Generate the SQL string as such:
SELECT 'CREATE TABLE table_name_copy AS SELECT '
|| LISTAGG (column_name, ', ') WITHIN GROUP (ORDER BY column_name)
|| ', (SELECT col_name FROM other_table
WHERE other_table.col_id = table_name.col_id) AS col_name'
|| ' FROM table_name'
FROM all_tab_cols
WHERE owner = 'OWNER'
AND table_name = 'TABLE_NAME'
AND column_name != 'COL_NAME'
If you want to run the above statement, you could use EXECUTE IMMEDIATE:
DECLARE
v_sql VARCHAR2(10000);
BEGIN
SELECT 'CREATE TABLE table_name_copy AS SELECT '
|| LISTAGG (column_name, ', ') WITHIN GROUP (ORDER BY column_name)
|| ', (SELECT col_name FROM other_table
WHERE other_table.col_id = table_name.col_id) AS col_name'
|| ' FROM table_name'
INTO v_sql
FROM all_tab_cols
WHERE owner = 'OWNER'
AND table_name = 'TABLE_NAME'
AND column_name != 'COL_NAME';
EXECUTE IMMEDIATE v_sql;
END;
/
If col_id column is fixed for both of the joined tables,
you may use user_tab_columns and user_tables dictionary views through the schema to produce new tables named as "table_name_copy" by using the following mechanism :
declare
v_ddl varchar2(4000);
v_cln varchar2(400);
begin
for c in ( select *
from user_tables t
where t.table_name in
( select c.table_name
from user_tab_columns c
where c.column_name = 'COL_ID' )
order by t.table_name )
loop
v_ddl := 'create table '||c.table_name||'_copy as
select ';
for d in ( select listagg('t1.'||column_name, ',') within group ( order by column_name ) cln
from user_tab_columns
where table_name = c.table_name
and column_name != 'COL_ID' )
loop
v_cln := v_cln||d.cln;
end loop;
v_ddl := v_ddl||v_cln;
v_ddl := v_ddl||', t2.col_id t2_id
from '||c.table_name||' t1
left outer join other_table t2 on ( t1.col_id = t2.col_id )';
execute immediate v_ddl;
v_ddl := null;
v_cln := null;
end loop;
end;
Maybe you can use a simple join and an asterisk to return all columns from the first table, like that:
CREATE TABLE table_name_copy AS
SELECT * FROM (
SELECT tab1.*, tab2.column_name
FROM table_name tab1 LEFT JOIN other_table tab2 ON tab1.col_id = tab2.col_id
);
I would try this (but I don't have Oracle SQL to test on so please leave me the benefit of the doubt)
CREATE TABLE table_name_copy AS
SELECT * FROM (
SELECT *, (SELECT col_name FROM other_table WHERE other_table.col_id = table_name.col_id) as col_name
FROM table_name`
)
edit:
then run
ALTER TABLE table_name_copy DROP COLUMN <old column>
to remove the column you don't need any more
I have table like this:
Table-1
Table-2
Table-3
Table-4
Table-5
each table is having many columns and one of the column name is employee_id.
Now, I want to write a query which will
1) return all the tables which is having this columns and
2) results should show the tables if the column is having values or empty values by passing employee_id.
e.g. show table name, column name from Table-1, Table-2,Table-3,... where employee_id='1234'.
If one of the table doesn't have this column, then it is not required to show.
I have verified with link, but it shows only table name and column name and not by passing some column values to it.
Also verified this, but here verifies from entire schema which I dont want to do it.
UPDATE:
Found a solution, but by using xmlsequence which is deprecated,
1)how do I make this code as xmltable?
2) If there are no values in the table, then output should have empty/null. or default as "YES" value
WITH char_cols AS
(SELECT /*+materialize */ table_name, column_name
FROM cols
WHERE data_type IN ('CHAR', 'VARCHAR2') and table_name in ('Table-1','Table-2','Table-3','Table-4','Table-5'))
SELECT DISTINCT SUBSTR (:val, 1, 11) "Employee_ID",
SUBSTR (table_name, 1, 14) "Table",
SUBSTR (column_name, 1, 14) "Column"
FROM char_cols,
TABLE (xmlsequence (dbms_xmlgen.getxmltype ('select "'
|| column_name
|| '" from "'
|| table_name
|| '" where upper("'
|| column_name
|| '") like upper(''%'
|| :val
|| '%'')' ).extract ('ROWSET/ROW/*') ) ) t ORDER BY "Table"
/
This query can be done in one step using the (non-deprecated) XMLTABLE.
Sample Schema
--Table-1 and Table-2 match the criteria.
--Table-3 has the right column but not the right value.
--Table-4 does not have the right column.
create table "Table-1" as select '1234' employee_id from dual;
create table "Table-2" as select '1234' employee_id from dual;
create table "Table-3" as select '4321' employee_id from dual;
create table "Table-4" as select 1 id from dual;
Query
--All tables with the column EMPLOYEE_ID, and the number of rows where EMPLOYEE_ID = '1234'.
select table_name, total
from
(
--Get XML results of dynamic query on relevant tables and columns.
select
dbms_xmlgen.getXMLType(
(
--Create a SELECT statement on each table, UNION ALL'ed together.
select listagg(
'select '''||table_name||''' table_name, count(*) total
from "'||table_name||'" where employee_id = ''1234'''
,' union all'||chr(10)) within group (order by table_name) v_sql
from user_tab_columns
where column_name = 'EMPLOYEE_ID'
)
) xml
from dual
) x
cross join
--Convert the XML data to relational.
xmltable('/ROWSET/ROW'
passing x.xml
columns
table_name varchar2(128) path 'TABLE_NAME',
total number path 'TOTAL'
);
Results
TABLE_NAME TOTAL
---------- -----
Table-1 1
Table-2 1
Table-3 0
Just try to use code below.
Pay your attention that may be nessecery clarify scheme name in loop.
This code works for my local db.
set serveroutput on;
DECLARE
ex_query VARCHAR(300);
num NUMBER;
emp_id number;
BEGIN
emp_id := <put your value>;
FOR rec IN
(SELECT table_name
FROM all_tab_columns
WHERE column_name LIKE upper('employee_id')
)
LOOP
num :=0;
ex_query := 'select count(*) from ' || rec.table_name || ' where employee_id = ' || emp_id;
EXECUTE IMMEDIATE ex_query into num;
if (num>0) then
DBMS_OUTPUT.PUT_LINE(rec.table_name);
end if;
END LOOP;
END;
I tried with the xml thing, but I get an error I cannot solve. Something about a zero size result. How difficult is it to solve this instead of raising exception?! Ask Oracle.
Anyway.
What you can do is use the COLS table to know what table has the employee_id column.
1) what table from table TABLE_LIKE_THIS (I assume column with table names is C) has this column?
select *
from COLS, TABLE_LIKE_THIS t
where cols.table_name = t
and cols.column_name = 'EMPLOYEE_ID'
-- think Oracle metadata/ think upper case
2) Which one has the value you are looking for: write a little chunk of Dynamic PL/SQL with EXECUTE IMMEDIATE to count the tables matching above condition
declare
v_id varchar2(10) := 'JP1829'; -- value you are looking for
v_col varchar2(20) := 'EMPLOYEE_ID'; -- column
n_c number := 0;
begin
for x in (
select table_name
from all_tab_columns cols
, TABLE_LIKE_THIS t
where cols.table_name = t.c
and cols.column_name = v_col
) loop
EXECUTE IMMEDIATE
'select count(1) from '||x.table_name
||' where Nvl('||v_col||', ''##'') = ''' ||v_id||'''' -- adding quotes around string is a little specific
INTO n_c;
if n_c > 0 then
dbms_output.put_line(n_C|| ' in ' ||x.table_name||' has '||v_col||'='||v_id);
end if;
-- idem for null values
-- ... ||' where '||v_col||' is null '
-- or
-- ... ||' where Nvl('||v_col||', ''##'') = ''##'' '
end loop;
dbms_output.put_line('done.');
end;
/
Hope this helps
I am trying to find a more efficient way to write PL/SQL Query to
to select insert from a table with 300+ columns, to the back up version of that table (same column names + 2 extra columns).
I could simply type out all the column names in the script (example below), but with that many names, it will bother me... :(
INSERT INTO
TABLE_TEMP
(column1, column2, column3, etc)
(SELECT column1, column2, column3, etc FROM TABLE WHERE id = USER_ID);
Thanks in advance
Specify literals/null for those two extra columns.
INSERT INTO
TABLE_TEMP
SELECT t1.*, null, null FROM TABLE t1 WHERE id = USER_ID
You can pretty easily build a column list for any given table:
select table_catalog
,table_schema
,table_name
,string_agg(column_name, ', ' order by ordinal_position)
from information_schema.columns
where table_catalog = 'catalog_name'
and table_schema = 'schema_name'
and table_name = 'table_name'
group by table_catalog
,table_schema
,table_name
That should get you nearly where you need to be.
The question tag says plsql, which is Oracle or one of its variants. Here is an example of doing it in Oracle:
drop table brianl.deleteme1;
drop table brianl.deleteme2;
CREATE TABLE brianl.deleteme1
(
a INTEGER
, b INTEGER
, c INTEGER
, efg INTEGER
);
CREATE TABLE brianl.deleteme2
(
b INTEGER
, c INTEGER
, d INTEGER
, efg INTEGER
);
DECLARE
l_ownerfrom VARCHAR2 (30) := 'BRIANL';
l_tablefrom VARCHAR2 (30) := 'DELETEME1';
l_ownerto VARCHAR2 (30) := 'BRIANL';
l_tableto VARCHAR2 (30) := 'DELETEME2';
l_comma VARCHAR2 (1) := NULL;
BEGIN
DBMS_OUTPUT.put_line ('insert into ' || l_ownerto || '.' || l_tableto || '(');
FOR eachrec IN ( SELECT f.column_name
FROM all_tab_cols f INNER JOIN all_tab_cols t ON (f.column_name = t.column_name)
WHERE f.owner = l_ownerfrom
AND f.table_name = l_tablefrom
AND t.owner = l_ownerto
AND t.table_name = l_tableto
ORDER BY f.column_name)
LOOP
DBMS_OUTPUT.put_line (l_comma || eachrec.column_name);
l_comma := ',';
END LOOP;
DBMS_OUTPUT.put_line (') select ');
l_comma := NULL;
FOR eachrec IN ( SELECT f.column_name
FROM all_tab_cols f INNER JOIN all_tab_cols t ON (f.column_name = t.column_name)
WHERE f.owner = l_ownerfrom
AND f.table_name = l_tablefrom
AND t.owner = l_ownerto
AND t.table_name = l_tableto
ORDER BY f.column_name)
LOOP
DBMS_OUTPUT.put_line (l_comma || eachrec.column_name);
l_comma := ',';
END LOOP;
DBMS_OUTPUT.put_line (' from ' || l_ownerfrom || '.' || l_tablefrom || ';');
END;
This results in this output:
insert into BRIANL.DELETEME2(
B
,C
,EFG
) select
B
,C
,EFG
from BRIANL.DELETEME1;
Nicely formatted:
INSERT INTO brianl.deleteme2 (b, c, efg)
SELECT b, c, efg
FROM brianl.deleteme1;