SQLite add Primary Key

Question

I created a table in Sqlite by using the CREATE TABLE AS syntax to create a table based on a SELECT statement. Now this table has no primary key b

Answer 1

As long as you are using CREATE TABLE, if you are creating the primary key on a single field, you can use:

CREATE TABLE mytable (
field1 TEXT,
field2 INTEGER PRIMARY KEY,
field3 BLOB,
);

With CREATE TABLE, you can also always use the following approach to create a primary key on one or multiple fields:

CREATE TABLE mytable (
field1 TEXT,
field2 INTEGER,
field3 BLOB,
PRIMARY KEY (field2, field1)
);

Reference: http://www.sqlite.org/lang_createtable.html

This answer does not address table alteration.