Insert into … values ( SELECT … FROM … )

Question

I am trying to INSERT INTO a table using the input from another table. Although this is entirely feasible for many database engines, I always seem to struggle to remember the correct syntax for the SQL engine of the day (MySQL, Oracle, SQL Server, Informix, and DB2).

Is there a silver-bullet syntax coming from an SQL standard (for example, SQL-92) that would allow me to insert the values without worrying about the underlying database?

Answer 1

Here's how to insert from multiple tables. This particular example is where you have a mapping table in a many to many scenario:

insert into StudentCourseMap (StudentId, CourseId) 
SELECT  Student.Id, Course.Id FROM Student, Course 
WHERE Student.Name = 'Paddy Murphy' AND Course.Name = 'Basket weaving for beginners'

(I realise matching on the student name might return more than one value but you get the idea. Matching on something other than an Id is necessary when the Id is an Identity column and is unknown.)

Answer 2

To get only one value in a multi value INSERT from another table I did the following in SQLite3:

INSERT INTO column_1 ( val_1, val_from_other_table ) 
VALUES('val_1', (SELECT  val_2 FROM table_2 WHERE val_2 = something))

Answer 3

For Microsoft SQL Server, I will recommend learning to interpret the SYNTAX provided on MSDN. With Google it's easier than ever, to look for syntax.

For this particular case, try

Google: insert site:microsoft.com

The first result will be http://msdn.microsoft.com/en-us/library/ms174335.aspx

scroll down to the example ("Using the SELECT and EXECUTE options to insert data from other tables") if you find it difficult to interpret the syntax given at the top of the page.

[ WITH <common_table_expression> [ ,...n ] ]
INSERT 
{
        [ TOP ( expression ) [ PERCENT ] ] 
        [ INTO ] 
        { <object> | rowset_function_limited 
          [ WITH ( <Table_Hint_Limited> [ ...n ] ) ]
        }
    {
        [ ( column_list ) ] 
        [ <OUTPUT Clause> ]
        { VALUES ( { DEFAULT | NULL | expression } [ ,...n ] ) [ ,...n     ] 
        | derived_table       <<<<------- Look here ------------------------
        | execute_statement   <<<<------- Look here ------------------------
        | <dml_table_source>  <<<<------- Look here ------------------------
        | DEFAULT VALUES 
        }
    }
}
[;]

This should be applicable for any other RDBMS available there. There is no point in remembering all the syntax for all products IMO.

Answer 4

Try:

INSERT INTO table1 ( column1 )
SELECT  col1
FROM    table2  

This is standard ANSI SQL and should work on any DBMS

It definitely works for:

• Oracle
• MS SQL Server
• MySQL
• Postgres
• SQLite v3
• Teradata
• DB2
• Sybase
• Vertica
• HSQLDB
• H2
• AWS RedShift
• SAP HANA

Answer 5

@Shadow_x99: That should work fine, and you can also have multiple columns and other data as well:

INSERT INTO table1 ( column1, column2, someInt, someVarChar )
SELECT  table2.column1, table2.column2, 8, 'some string etc.'
FROM    table2
WHERE   table2.ID = 7;

Edit: I should mention that I've only used this syntax with Access, SQL 2000/2005/Express, MySQL, and PostgreSQL, so those should be covered. A commenter has pointed out that it'll work with SQLite3.

Answer 6

If you go the INSERT VALUES route to insert multiple rows, make sure to delimit the VALUES into sets using parentheses, so:

INSERT INTO `receiving_table`
  (id,
  first_name,
  last_name)
VALUES 
  (1002,'Charles','Babbage'),
  (1003,'George', 'Boole'),
  (1001,'Donald','Chamberlin'),
  (1004,'Alan','Turing'),
  (1005,'My','Widenius');

Otherwise MySQL objects that "Column count doesn't match value count at row 1", and you end up writing a trivial post when you finally figure out what to do about it.