database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-13 07:41:39 +03:00
Code Activity

Allow psql's \g and \gx commands to transiently change \pset options.

Browse Source 
We invented \gx to allow the "\pset expanded" flag to be forced on
for the duration of one command output, but that turns out to not
be nearly enough to satisfy the demand for variant output formats.
Hence, make it possible to change any pset option(s) for the duration
of a single command output, by writing "option=value ..." inside
parentheses, for example
	\g (format=csv csv_fieldsep='\t') somefile

\gx can now be understood as a shorthand for including expanded=on
inside the parentheses.

Patch by me, expanding on a proposal by Pavel Stehule

Discussion: https://postgr.es/m/CAFj8pRBx9OnBPRJVtfA5ycUpySge-XootAXAsv_4rrkHxJ8eRg@mail.gmail.com
This commit is contained in:
Tom Lane
2020-04-07 17:46:29 -04:00
parent 0f5ca02f53
commit b63c293bcb
8 changed files with 315 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
doc/src/sgml/ref/psql-ref.sgml
View File

@ -2105,12 +2105,34 @@ Tue Oct 26 21:40:57 CEST 1999
<varlistentry>
<term><literal>\g [ <replaceable class="parameter">filename</replaceable> ]</literal></term>
<term><literal>\g [ |<replaceable class="parameter">command</replaceable> ]</literal></term>
<term><literal>\g [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ <replaceable class="parameter">filename</replaceable> ]</literal></term>
<term><literal>\g [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ |<replaceable class="parameter">command</replaceable> ]</literal></term>
<listitem>
<para>
Sends the current query buffer to the server for execution.
If an argument is given, the query's output is written to the named
</para>
<para>
If parentheses appear after <literal>\g</literal>, they surround a
space-separated list
of <replaceable class="parameter">option</replaceable><literal>=</literal><replaceable class="parameter">value</replaceable>
formatting-option clauses, which are interpreted in the same way
as <literal>\pset</literal>
<replaceable class="parameter">option</replaceable>
<replaceable class="parameter">value</replaceable> commands, but take
effect only for the duration of this query. In this list, spaces are
not allowed around <literal>=</literal> signs, but are required
between option clauses.
If <literal>=</literal><replaceable class="parameter">value</replaceable>
is omitted, the
named <replaceable class="parameter">option</replaceable> is changed
in the same way as for
<literal>\pset</literal> <replaceable class="parameter">option</replaceable>
with no explicit <replaceable class="parameter">value</replaceable>.
</para>
<para>
If a <replaceable class="parameter">filename</replaceable>
or <literal>|</literal><replaceable class="parameter">command</replaceable>
argument is given, the query's output is written to the named
file or piped to the given shell command, instead of displaying it as
usual. The file or command is written to only if the query
successfully returns zero or more tuples, not if the query fails or
@ -2119,13 +2141,15 @@ Tue Oct 26 21:40:57 CEST 1999
<para>
If the current query buffer is empty, the most recently sent query is
re-executed instead. Except for that behavior, <literal>\g</literal>
without an argument is essentially equivalent to a semicolon.
A <literal>\g</literal> with argument is a <quote>one-shot</quote>
alternative to the <command>\o</command> command.
without any arguments is essentially equivalent to a semicolon.
With arguments, <literal>\g</literal> provides
a <quote>one-shot</quote> alternative to the <command>\o</command>
command, and additionally allows one-shot adjustments of the
output formatting options normally set by <literal>\pset</literal>.
</para>
<para>
If the argument begins with <literal>|</literal>, then the entire remainder
of the line is taken to be
When the last argument begins with <literal>|</literal>, the entire
remainder of the line is taken to be
the <replaceable class="parameter">command</replaceable> to execute,
and neither variable interpolation nor backquote expansion are
performed in it. The rest of the line is simply passed literally to
@ -2246,12 +2270,14 @@ hello 10
<varlistentry>
<term><literal>\gx [ <replaceable class="parameter">filename</replaceable> ]</literal></term>
<term><literal>\gx [ |<replaceable class="parameter">command</replaceable> ]</literal></term>
<term><literal>\gx [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ <replaceable class="parameter">filename</replaceable> ]</literal></term>
<term><literal>\gx [ (<replaceable class="parameter">option</replaceable>=<replaceable class="parameter">value</replaceable> [...]) ] [ |<replaceable class="parameter">command</replaceable> ]</literal></term>
<listitem>
<para>
<literal>\gx</literal> is equivalent to <literal>\g</literal>, but
forces expanded output mode for this query. See <literal>\x</literal>.
<literal>\gx</literal> is equivalent to <literal>\g</literal>, except
that it forces expanded output mode for this query, as
if <literal>expanded=on</literal> were included in the list of
<literal>\pset</literal> options. See also <literal>\x</literal>.
</para>
</listitem>
</varlistentry>
@ -4879,9 +4905,31 @@ second | three
-[ RECORD 4 ]-
first | 4
second | four
</programlisting></para>
</programlisting>
</para>
<para>
<para>
Also, these output format options can be set for just one query by using
<literal>\g</literal>:
<programlisting>
peter@localhost testdb=&gt; <userinput>SELECT * FROM my_table</userinput>
peter@localhost testdb-&gt; <userinput>\g (format=aligned tuples_only=off expanded=on)</userinput>
-[ RECORD 1 ]-
first | 1
second | one
-[ RECORD 2 ]-
first | 2
second | two
-[ RECORD 3 ]-
first | 3
second | three
-[ RECORD 4 ]-
first | 4
second | four
</programlisting>
</para>
<para>
When suitable, query results can be shown in a crosstab representation
with the <command>\crosstabview</command> command:
<programlisting>