2.3. Creating a New Table
You can create a new table by specifying the table name, along with all column names and their types:
CREATE TABLE weather ( city varchar(80), temp_lo int, -- low temperature temp_hi int, -- high temperature prcp real, -- precipitation date date );
You can enter this into
psql with the line
psql will recognize that the command
is not terminated until the semicolon.
White space (i.e., spaces, tabs, and newlines) can be used freely
in SQL commands. That means you can type the command aligned
differently than above, or even all on one line. Two dashes
--”) introduce comments.
Whatever follows them is ignored up to the end of the line. SQL
is case insensitive about key words and identifiers, except
when identifiers are double-quoted to preserve the case (not done
varchar(80) specifies a data type that can store
arbitrary character strings up to 80 characters in length.
int is the normal integer type.
a type for storing single precision floating-point numbers.
date should be self-explanatory. (Yes, the column of
date is also named
This might be convenient or confusing — you choose.)
PostgreSQL supports the standard
interval, as well as other types of general utility
and a rich set of geometric types.
PostgreSQL can be customized with an
arbitrary number of user-defined data types. Consequently, type
names are not key words in the syntax, except where required to
support special cases in the SQL standard.
The second example will store cities and their associated geographical location:
CREATE TABLE cities ( name varchar(80), location point );
point type is an example of a
PostgreSQL-specific data type.