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Typing in the Query Buffer

Typing in the query buffer is similar to typing at a operating system command prompt. However, at a operating system command prompt, Enter completes each command. In psql, commands are completed only when you enter a semicolon (;) or backslash-g (\g). Here's a good example. Let's do SELECT 1 + 3; but in a different way. See figure [*].4.2

  
Figure: Multi-line query
\begin{figure}\begin{list}{}{
\setlength{\rightmargin}{\leftmargin}
\raggedrigh...
...{}-{}-{}-
\par ~~~~~~~4
\par (1~row)~\\
~\\
~test=>\end{list}\par
\end{figure}

Notice how the query is spread the over three lines. The semicolon was the thing that told psql to send the query to the server. We could easily have replaced the semicolon with backslash-g. I don't recommend you type queries as ugly as this one, but longer queries will benefit from the ability to spread them over multiple lines. You may notice that part of the query is in uppercase, and some of it is in lowercase. Unless you are typing a string in quotes, the POSTGRESQL server doesn't care whether words are uppercase or lowercase. For stylistic reasons, I recommend words special to POSTGRESQL be entered in all uppercase, and user-supplied words in lowercase.

Try some queries on your own involving arithmetic. Each computation must start with the word SELECT, then your computation, and finally a semicolon or backslash-g to finish. For example, SELECT 4 * 10; would return 40. In psql, addition is plus (+), subtraction is minus (-), multiplication is asterisk (*), and division is forward slash (/).

If you have readline4.3 installed, psql will even allow you to use your arrow keys. Your left and right arrow keys allow you to move around, and the up and down arrows retrieve previously typed query strings.


next up previous contents index
Next: Displaying the Query Buffer Up: Controlling a Session Previous: Controlling a Session
Bruce Momjian
1999-11-21