Question

What is difference between these in terms of constraints *keys* etc.

Select Into Statement

SELECT column1, column2, someInt, someVarChar 
INTO ItemBack1 
FROM table2
WHERE table2.ID = 7

Insert Into Statement

INSERT INTO table1 ( column1, column2, someInt, someVarChar )
SELECT  table2.column1, table2.column2,
FROM    table2
WHERE   table2.ID = 7

and also

Create table ramm as select * from rammayan

Edit 1:

Database SQL Server 2008

Answer 1

I’m going to assume MySQL here.

The first two are identical, as the documentation states.

The third statement allows for both table creation and population, though your syntax is wrong up there; look at the right syntax for more info.

Update

It’s SQL Server =p

SELECT column1, column2, someInt, someVarChar 
INTO ItemBack1 
FROM table2
WHERE table2.ID = 7

The first statement will automatically create the ItemBack1 table, based on table2.

INSERT INTO table1 ( column1, column2, someInt, someVarChar )
SELECT  table2.column1, table2.column2,
FROM    table2
WHERE   table2.ID = 7

The second second statement requires that table1 already exists.

See also: http://blog.sqlauthority.com/2007/08/15/sql-server-insert-data-from-one-table-to-another-table-insert-into-select-select-into-table/

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If there’s any difference in constraints, it would be because the second statement depends on what you have already created (and if the table is populated, etc.).

Btw, the third statement is Oracle(tm) and is the same as the first statement.