How to delete multiple tables in single query in DB2?
DROP TABLE tableName1,tableName2;
If you tables are in hierarchy - you can use
DROP TABLE HIERARCHY operation, if they aren't - unfortunatly, you can't delete tables in single query and you may delete them separatly.
I tried a lot of things but it never worked, Ultimately this is what works.
db2 "Select 'DROP TABLE ', tabname, ';' from syscat.tables where owner='DB2INST1'" >> filename
This would essentially generate a file called filename, It will have the drop table command for all the tables, You have to open this file up and REMOVE all the tables you don't want to drop and leave the ones which you need. Verify again.
Run this using:
db2 -tvf filename.
Related
I am trying to drop multiple tables, using the following code, but it raises an error.
the code:
PROC SQL ;
CONNECT TO teradata AS TERADATA (server=dbc mode=teradata) ;
EXECUTE (drop table TABLE_NAME1, TABLE_NAME2, TABLE_NAME3 ) BY teradata ;
DISCONNECT FROM teradata ;
QUIT ;
the error:
syntax error: expecting something between NAME1 and TABLE
If you look at the documentation for drop in Teradata, you will see that it operates on only one table:
Drops the definition for the specified table from the data dictionary and drops the object from its containing database or user, depending on the keyword specified.
This is how most databases work. You need to do three drops:
drop table TABLE_NAME1;
drop table TABLE_NAME2;
drop table TABLE_NAME3;
You can delete all objects in the database with one command:
DELETE DATABASE name_database;
but also views, triggers, stored procedures, user-defined functions, and macros will be deleted.
I'm trying to write a query that RENAMEs multiple table columns at once. According to the documentation, the syntax is:
ALTER TABLE table_name
RENAME old_col_a AS new_col_a
, RENAME old_col_b AS new_col_b...;
However, in doing so I get a syntax error located on the comma after the first RENAME clause:
ERROR: syntax error at or near ","
LINE 3: , RENAME
^
SQL state: 42601
Character: 1
The query works for multiple DROP/ALTER/ADD columns and for single RENAMEs. I just can't for the life of me figure out why this error is occurring.
You need to use multiple ALTER statements:
ALTER TABLE table_name
RENAME COLUMN old_col_a TO new_col_a;
ALTER TABLE table_name
RENAME COLUMN old_col_b TO new_col_b;
ALTER TABLE
All the forms of ALTER TABLE that act on a single table, except RENAME, SET SCHEMA, ATTACH PARTITION, and DETACH PARTITION can be combined into a list of multiple alterations to be applied together. For example, it is possible to add several columns and/or alter the type of several columns in a single command. This is particularly useful with large tables, since only one pass over the table need be made.
I am new to oracle. I would like to ask if there exist one single command that could copy table a to table b such that table b would have the same data, same structure and same access priviledge as table a? I would like to make a duplicate of a table which contain the same behavior.
Someone please correct me if I am wrong, but I don't think you can copy it with privileges/indexes as it is. That might be becasuse you need to give a new name for the index,primary key etc, and the database will not know what name needs to be given to these. So you can do this.
Run this to get the DDL of the table you want and then replace it with new table name. (my source table is TZ_TEST and I will create TZ_TEST_NEW. (Thanks to this answer for get_ddl command)
select replace(
(SELECT dbms_metadata.get_ddl( 'TABLE', 'TZ_TEST' ) FROM DUAL),
'TZ_TEST',
'TZ_TEST_NEW')
from dual
Execute the DDL
Use this to get grant permissions
select replace(
(select DBMS_METADATA.GET_DEPENDENT_DDL('OBJECT_GRANT','TZ_TEST') FROM DUAL),
'TZ_TEST',
'TZ_TEST_NEW') from dual
Similarly use DBMS_METADATA to get constraints/index etc. Execute these statmetns.
Insert data
insert into TZ_TEST_NEW
select * from TZ_TEST
Please remember that if you have an auto generated primary key, then while inserting data, you need to exclude that column from insert and select statments.
Anyone please feel free to add if I missed something.
Also we can create a procedure which can so all this but you need to be careful with all the steps. So once you do it couple of times and it works, we can create a procedure for it.
If you are using TOAD for Oracle, then select the table name and press F4. Then select script tab in the describe window.
This will generate the table script. You just need to use Search/Replace to change the table name and execute the script.
The newly created table will contain the same behavior.
I would do it in two steps:
Use CTAS i.e. create table as select .. to first create a copy of the table with new name with the data. You could also use PARALLEL and NOLOGGING feature to increase the performance.
For example,
create table t parallel 4 nologging as select * from emp;
Get the associated structures like indexes, constraints etc. using DBMS_METADATA.GET_DEPENDENT_DDL and execute it. But, you need to first replace the table_name to your new table_name as you have created in step 1.
CTAS would be much faster than traditional insert.
I need a query to create a table which is the exact replica but with different table name and without any data from the source table using a sql query!
You can try this
SELECT * INTO Table_Copy
FROM Table
where 1=2
It will create a empty table with the same structure.
SQL Server Management Studio
Object Explorer
Connect -> Your server
Databases -> Choose Database
Tables
Right Click Your Table
Script Table as -> Create To -> New Query Editor Window
Jonathan has it (upvoted), and you should probably go with that because it's more portable. I normally use something similar:
SELECT TOP 0 * INTO [New_Table] FROM [Old_Table]
I think this better expresses what you're doing, but I like Jonathan's because 'TOP 0' is SQL Server specific, and so his is more portable.
For MySQL, you can call SHOW CREATE TABLE table_name;
It will display a CREATE TABLE query. Simply change the table name in that query and you're good to go.
http://dev.mysql.com/doc/refman/5.1/en/show-create-table.html
If you use Postgresql:
CREATE TABLE LIKE table_name
http://www.postgresql.org/docs/8.1/static/sql-createtable.html
SELECT * INTO Table_Copy
FROM Table
where 1=2
This worked very well, when i tried to create a replica of the table without any data's.
SELECT * INTO Table_Copy
FROM Table
This will create a replica with the data's too.
This can help you:
CREATE TABLE foo AS SELECT...
Read more here
select * into newtablename from sourcetablename
go
truncate newtablename
go
That will result in an exact copy but it also copies the data at first which you remove with the truncate statement.
create table <new table name> as select * from <old tale name from which you would like to extract data>
It will create a new table with a different name but will copy all existing data from the old table to new table.
in postgres you can use INHERITS or LIKE keyword to make replica of a table(only copies structure of the table)
CREATE TABLE client_new (LIKE client);
or
CREATE TABLE client_new () INHERITS (client)
Use of INHERITS creates a persistent relationship between the new child table and its parent table(s). Schema modifications to the parent(s) normally propagate to children as well, and by default the data of the child table is included in scans of the parent(s).
LIKE clause specifies a table from which the new table automatically copies all column names, their data types, and their not-null constraints.Unlike INHERITS, the new table and original table are completely decoupled after creation is complete. Changes to the original table will not be applied to the new table, and it is not possible to include data of the new table in scans of the original table.
What is the SQL command to copy a table from one database to another database?
I am using MySQL and I have two databases x and y. Suppose I have a table in x called a and I need to copy that table to y database.
Sorry if the question is too novice.
Thanks.
If the target table doesn't exist....
CREATE TABLE dest_table AS (SELECT * FROM source_table);
If the target table does exist
INSERT INTO dest_table (SELECT * FROM source_table);
Caveat: Only tested in Oracle
If your two database are separated, the simplest thing to do would be to create a dump of your table and to load it into the second database. Refer to your database manual to see how a dump can be performed.
Otherwise you can use the following syntax (for MySQL)
INSERT INTO database_b.table (SELECT * FROM database_a.table)
Since your scenario involves two different databases, the correct query should be...
INSERT INTO Y..dest_table (SELECT * FROM source_table);
Query assumes, you are running it using X database.
If you just want to copy the contents, you might be looking for select into:
http://www.w3schools.com/Sql/sql_select_into.asp. This will not create an identical copy though, it will just copy every row from one table to another.
At the command line
mysqldump somedb sometable -u user -p | mysql otherdb -u user -p
then type both passwords.
This works even if they are on different hosts (just add the -h parameter as usual), which you can't do with insert select.
Be careful not to accidentally pipe into the wrong db or you will end up dropping the sometable table in that db! (The dump will start with 'drop table sometable').
insert blah from select suggested by others is good for copying the data under mysql.
If you want to copy the table structure you might want to use the show create table Tablename; statement.