You can create a new table by using the CREATE TABLE command, 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 ); |
White space (that is, spaces, tabs, and line breaks) 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. However, identifiers can be placed in double-quotes to preserve the case.
varchar(80) specifies a data type that can store arbitrary character strings up to 80 characters in length. int is the normal integer type. real is a type for storing single precision floating-point numbers. date should be self-explanatory. (Yes, the column of type date is also named date. This may be convenient or confusing—you choose.)
PostgreSQL supports the usual SQL types (int, smallint, real, double precision, char(N), varchar(N), date, time, timestamp, and 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 syntactical keywords 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 ); |
If you do not need a table any longer or if you want to recreate it differently, you can remove it using the following command:
DROP TABLE tablename; |