Does sqlite support the SELECT INTO statement?
Actually I am trying to save the data in table1 into table2 as a backup of my database before modifying the data.
When I try using the SELECT INTO statement:
SELECT * INTO equipments_backup FROM equipments;
I get a syntax error:
"Last Error Message:near "INTO":syntax
error".
Instead of
SELECT * INTO equipments_backup FROM equipments
try
CREATE TABLE equipments_backup AS SELECT * FROM equipments
sqlite does not support SELECT INTO.
You can probably use this form instead:
INSERT INTO equipments_backup SELECT * FROM equipments;
SQlite didn't have INSERT INTO syntax.
In 2019, I use TEMPORARY keyword to create temporary table and INSERT data to temp table:
CREATE TEMPORARY TABLE equipments_backup(field1 TEXT, field2 REAL)
INSERT INTO equipments_backup SELECT field1, field2 FROM equipments
Related
Kindly help me writing below query in openquery.Thanks in advance
INSERT INTO Tablename
SELECT * FROM tablename1 WHERE insertionorderid IN (
SELECT orderid FROM temp_table2)
If you are trying to insert into SQL Server the syntax would be
INSERT INTO dbo.[YOURTABLE] SELECT * FROM [MATCHING_TABLE] WHERE CLAUSE
The caveat here is that the two tables must have identical schemas or you will have to explicitly define the columns. Also this will not work properly for tables with identity columns
I'm running Oracle 11G. Assume I have table named TEST_TABLE. I can see it when run :
SQL> SELECT TABLE_NAME FROM ALL_TABLES WHERE TABLE_NAME='TEST_TABLE';
TABLE_NAME
------------------------------
TEST_TABLE
But when I try to get table content I get an error:
SQL> SELECT * FROM table (TEST_TABLE);
SELECT * FROM table (TEST_TABLE)
*
ERROR at line 1:
ORA-00904: "TEST_TABLE": invalid identifier
Any help will be greatly appreciated !
SELECT * FROM table (TEST_TABLE);
That is the syntax for using a table function. Quite an advanced topic, not what you are looking for.
To access a table, simply do
SELECT * FROM TEST_TABLE;
How to return auto generated column values from sqlite database in c#. I'm using Sqlite.data.dll.
Tried by executing query : "select last_insert_rowid() but it doesn;t seem to work as it is returning 0s. I'm using SqliteDataReader object to get the result.
Thanks
I tried these commands, and it worked fine (even if the last_insert_rowid() call is from another transaction):
sqlite> create table mytable(pk integer primary key, other stuff);
sqlite> insert into mytable values(null, 42);
sqlite> select last_insert_rowid();
1
The only requirement of last_insert_rowid() is that it is called on the same database connection; please check that you didn't open another one.
is your id is incremented? then try this:
SELECT max(id)
or you can refer to this post
Click HERE
In my project, I have a database in SQL which was working fine. But now I have to make the application support oracle db too.
Some limitations I found out was that in Oracle, there is no bit field and the table name cannot be greater than 30 char. Is there any other limitation that I need to keep in mind.
Any suggestion from past experience will be helpful.
If I recall correctly from my earlier Oracle days:
there's no IDENTITY column specification in Oracle (you need to use sequences instead)
you cannot simply return a SELECT (columns) from a stored procedure (you need to use REF CURSOR)
of course, all stored procs/funcs are different (Oracle's PL/SQL is not the same as T-SQL)
The SQL ISNULL counterpart in Oracle is NVL
select ISNULL(col, 0)...
select NVL(col, 0)...
You will also struggle if you attempt to select without a from in Oracle. Use dual:
select 'Hello' from DUAL
Bear in mind also, that in Oracle there is the distinction between PL/SQL (Procedural SQL) and pure SQL. They are two distinct and separate languages, that are commonly combined.
Varchar in Oracle Databases called
varchar2 is limited to 4000
characters
Oracles concept of temporary tables is different, they have a global redefined structure
by default sort order and string compare is case-sensitive
When you add a column to a select *
Select * from table_1 order by id;
you must prefix the * by the table_name or an alias
Select
(row_number() over (order by id)) rn,
t.*
from table_1 t
order by id;
Oracle doesn't distinguish between null and '' (empty string). For insert and update you ca use '', but to query you must use null
create table t1 (
id NUMBER(10),
val varchar2(20)
);
Insert into t1 values (1, '');
Insert into t1 values (2, null);
Select * from t1 where stringval = 0; -- correct but empty
Select * from t1 where stringval is null; -- returns both rows
ORACLE do not support TOP clause. Instead of TOP you can use ROWNUM.
SQL Server: TOP (Transact-SQL)
SELECT TOP 3 * FROM CUSTOMERS
ORACLE: ROWNUM Pseudocolumn
SELECT * FROM CUSTOMERS WHERE ROWNUM <= 3
How do I alter column in sqlite?
This is in Postgresql
ALTER TABLE books_book ALTER COLUMN publication_date DROP NOT NULL;
I believe there is no ALTER COLUMN in sqlite at all, only ALTER TABLE is supported.
Any idea? Thanks!
There's no ALTER COLUMN in sqlite.
I believe your only option is to:
Rename the table to a temporary name
Create a new table without the NOT NULL constraint
Copy the content of the old table to the new one
Remove the old table
This other Stackoverflow answer explains the process in details
While it is true that the is no ALTER COLUMN, if you only want to rename the column, drop the NOT NULL constraint, or change the data type, you can use the following set of dangerous commands:
PRAGMA writable_schema = 1;
UPDATE SQLITE_MASTER SET SQL = 'CREATE TABLE BOOKS ( title TEXT NOT NULL, publication_date TEXT)' WHERE NAME = 'BOOKS';
PRAGMA writable_schema = 0;
You will need to either close and reopen your connection or vacuum the database to reload the changes into the schema.
For example:
Y:\> **sqlite3 booktest**
SQLite version 3.7.4
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> **create table BOOKS ( title TEXT NOT NULL, publication_date TEXT NOT
NULL);**
sqlite> **insert into BOOKS VALUES ("NULLTEST",null);**
Error: BOOKS.publication_date may not be NULL
sqlite> **PRAGMA writable_schema = 1;**
sqlite> **UPDATE SQLITE_MASTER SET SQL = 'CREATE TABLE BOOKS ( title TEXT NOT
NULL, publication_date TEXT)' WHERE NAME = 'BOOKS';**
sqlite> **PRAGMA writable_schema = 0;**
sqlite> **.q**
Y:\> **sqlite3 booktest**
SQLite version 3.7.4
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> **insert into BOOKS VALUES ("NULLTEST",null);**
sqlite> **.q**
REFERENCES FOLLOW:
pragma writable_schema
When this pragma is on, the SQLITE_MASTER tables in which database can be changed using ordinary UPDATE, INSERT, and DELETE statements. Warning: misuse of this pragma can easily result in a corrupt database file.
[alter table](From http://www.sqlite.org/lang_altertable.html)
SQLite supports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table.
SQLite supports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table. But you can alter table column datatype or other property by the following steps.
BEGIN TRANSACTION;
CREATE TEMPORARY TABLE t1_backup(a,b);
INSERT INTO t1_backup SELECT a,b FROM t1;
DROP TABLE t1;
CREATE TABLE t1(a,b);
INSERT INTO t1 SELECT a,b FROM t1_backup;
DROP TABLE t1_backup;
COMMIT
For more detail you can refer the link.
CREATE TABLE temp_Table(x,y[,etc]);
INSERT INTO temp_Table SELECT * FROM Table;
DROP TABLE Table;
ALTER TABLE temp_Table RENAME TO Table;
Thanks for helping me to find a definitive method!
ALTER COLUMN does not exist in SQLite.
Only Supported alter operations:
Alter Table Name
Alter Table Column Name
Add New Column
Drop Column
Alex Jasmin's answer shows possible way
Reference:
Sqlite Alter Table