I have created a table2 with SQL query: create table2 as select * from table1
Create table as select ... doesn't retain all column properties from table1 in table2.
Is it possible to generate an SQL file to ALTER table2 column properties (DATA_LENGTH,DATA_PRECISION,DATA_SCALE,DEFAULT_LENGTH,DATA_DEFAULT) with all column properties from table1?
Thanks!
--drop table table2;
create table table1 (
x number(10, 2) default 10,
y varchar2(200) default 'NA'
);
create table table2 as select * from table1;
Let us try for data_default:
create table search_user_tab_columns as
select table_name, column_name, to_lob(DATA_DEFAULT) dd
from user_tab_columns
where table_name = 'TABLE1';
As data_default is a long data in user_tab_columns we have to create an intermediate
search_user_tab_columns (dummy) :-(
select 'ALTER TABLE "' || table_name || '" MODIFY "' || column_name || '" DEFAULT ' || Dd || ';'
from search_user_tab_columns
where table_name = 'TABLE1';
Note:
SELECT DBMS_METADATA.GET_DDL('TABLE','<TABLE_NAME>','<SCHEMA_NAME>') from dual;
This is better way of doing this if creating a table from an existing table . But sometimes you may try this for specific purposes.
If you only need to get the properties.
SELECT DBMS_METADATA.GET_DDL('TABLE','<TABLE_NAME>','<SCHEMA_NAME>') from dual;
try this:
you can see all properties
select column_name as "Name"
, nullable as "Null?"
, concat(concat(concat(data_type,'('),data_length),')') as "Type"
from user_tab_columns
where table_name = 'MY_TABLE';
Related
I am trying to create a view by joining two tables. These two tables have a few columns with the same name. Which gives an error
SQL Error [42701]: ERROR: column "column_name" specified more than once
I cannot use column names while creating the view as there are 30+ columns and new columns will be added to both tables over the period of time. Hence, I have to use * to get all the columns.
Now, to eliminate columns which exist in both the table, I went ahead and did this:
SELECT 'SELECT ' || STRING_AGG('u2.' || column_name, ', ') || ' FROM schema_name.table_name u2'
FROM information_schema.columns
WHERE table_name = 'table_name'
AND table_schema = 'schema_name'
AND column_name NOT IN ('column_name');
This gives me the query to select data from schema_name.table_name without the column column_name. Great!!
The problem: How do I execute the result of the above query?
I tried PREPARE statement, it is just executing the above query and not the result of the above query.
Also, creating a temporary table with no column "column_name" isn't a viable solution.
You need to prepare a dynamic query and then EXECUTE it. It would be something like this:
DO
$do$
BEGIN
EXECUTE (
SELECT CONCAT('CREATE VIEW temp_view AS SELECT ',
-- SELECT table1 columns here
(SELECT STRING_AGG('u1.' || column_name, ', ')
FROM information_schema.columns
WHERE table_name = 'table1'
AND table_schema = 'schema_name'
-- AND column_name NOT IN ('column_name') -- not omitting for table1
),
', ',
-- SELECT table2 columns here
(SELECT STRING_AGG('u2.' || column_name, ', ')
FROM information_schema.columns
WHERE table_name = 'table2'
AND table_schema = 'schema_name'
AND column_name NOT IN ('column_name')),
-- Dynamically prepare the FROM and JOIN clauses
' FROM table1 u1 JOIN table2 u2 ON u1.id = u2.table1_id'));
END
$do$;
CHECK DEMO
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 1 table having 40 columns. Out of 40 columns only 5 columns are NOT NULL and rest of the columns are set as NULL. How can i set all NULL column to NOT NULL in one time or in TOAD. Is there any possibility to do this except manually set as NOT NULL.
You can use the Alter Table command to do so. This way:
ALTER TABLE table_name
MODIFY (column_1 column_type NOT NULL,
column_2 column_type NOT NULL,
...
column_n column_type);
This will accomplish the changes in all columns at once. Also if your table already has data with null values on those columns, you will have to define default values as well. Here is a sample:
ALTER TABLE table_name
MODIFY (column_1 varchar2(100) DEFAULT 'some default' NOT NULL,
column_2 varchar2(75) DEFAULT 'Some Value' NOT NULL);
Alter table will work .
alter table [nameOfYourTable] modify [nameOfColumn] [dataType] not null
You could loop through USER_TAB_COLUMNS ( ALL_TAB_COLUMNS with owner = 'schema') and ALTER using EXECUTE IMMEDIATE.
You could first update the table containing existing NULLs with appropriate value before running this.
SET SERVEROUTPUT ON
BEGIN
FOR q IN (
SELECT 'ALTER TABLE ' || table_name || ' MODIFY ' || column_name || ' NOT NULL' AS query
FROM user_tab_columns
WHERE table_name = 'YOURTABLE'
AND NULLABLE = 'Y'
)
LOOP
DBMS_OUTPUT.PUT_LINE(q.query);
EXECUTE IMMEDIATE q.query;
END LOOP;
END;
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 have many tables that have the same column 'customer_number'.
I can get a list of all these table by query:
SELECT table_name FROM ALL_TAB_COLUMNS
WHERE COLUMN_NAME = 'customer_number';
The question is how do I get all the records that have a specific customer number from all these tables without running the same query against each of them.
To get record from a table, you have write a query against that table. So, you can't get ALL the records from tables with specified field without a query against each one of these tables.
If there is a subset of columns that you are interested in and this subset is shared among all tables, you may use UNION/UNION ALL operation like this:
select * from (
select customer_number, phone, address from table1
union all
select customer_number, phone, address from table2
union all
select customer_number, phone, address from table3
)
where customer_number = 'my number'
Or, in simple case where you just want to know what tables have records about particular client
select * from (
select 'table1' src_tbl, customer_number from table1
union all
select 'table2', customer_number from table2
union all
select 'table3', customer_number from table3
)
where customer_number = 'my number'
Otherwise you have to query each table separatelly.
DBMS_XMLGEN enables you to run dynamic SQL statements without custom PL/SQL.
Sample Schema
create table table1(customer_number number, a number, b number);
insert into table1 values(1,1,1);
create table table2(customer_number number, a number, c number);
insert into table2 values(2,2,2);
create table table3(a number, b number, c number);
insert into table3 values(3,3,3);
Query
--Get CUSTOMER_NUMBER and A from all tables with the column CUSTOMER_NUMBER.
--
--Convert XML to columns.
select
table_name,
to_number(extractvalue(xml, '/ROWSET/ROW/CUSTOMER_NUMBER')) customer_number,
to_number(extractvalue(xml, '/ROWSET/ROW/A')) a
from
(
--Get results as XML.
select table_name,
xmltype(dbms_xmlgen.getxml(
'select customer_number, a from '||table_name
)) xml
from user_tab_columns
where column_name = 'CUSTOMER_NUMBER'
);
TABLE_NAME CUSTOMER_NUMBER A
---------- --------------- -
TABLE1 1 1
TABLE2 2 2
Warnings
These overly generic solutions often have issues. They won't perform as well as a plain old SQL statements and they are more likely to run into bugs. In general, these types of solutions should be avoided for production code. But they are still very useful for ad hoc queries.
Also, this solution assumes that you want the same columns from each row. If each row is different then things get much more complicated and you may need to look into technologies like ANYDATASET.
I assume you want to automate this. Two approaches.
SQL to generate SQL scripts
.
spool run_rep.sql
set head off pages 0 lines 200 trimspool on feedback off
SELECT 'prompt ' || table_name || chr(10) ||
'select ''' || table_name ||
''' tname, CUSTOMER_NUMBER from ' || table_name || ';' cmd
FROM all_tab_columns
WHERE column_name = 'CUSTOMER_NUMBER';
spool off
# run_rep.sql
PLSQL
Similar idea to use dynamic sql:
DECLARE
TYPE rcType IS REF CURSOR;
rc rcType;
CURSOR c1 IS SELECT table_name FROM all_table_columns WHERE column_name = 'CUST_NUM';
cmd VARCHAR2(4000);
cNum NUMBER;
BEGIN
FOR r1 IN c1 LOOP
cmd := 'SELECT cust_num FROM ' || r1.table_name ;
OPEN rc FOR cmd;
LOOP
FETCH rc INTO cNum;
EXIT WHEN rc%NOTFOUND;
-- Prob best to INSERT this into a temp table and then
-- select * that to avoind DBMS_OUTPUT buffer full issues
DBMS_OUTPUT.PUT_LINE ( 'T:' || r1.table_name || ' C: ' || rc.cust_num );
END LOOP;
CLOSE rc;
END LOOP;
END;