Add \gdesc psql command.

This command acts somewhat like \g, but instead of executing the query
buffer, it merely prints a description of the columns that the query
result would have.  (Of course, this still requires parsing the query;
if parse analysis fails, you get an error anyway.)  We accomplish this
using an unnamed prepared statement, which should be invisible to psql
users.

Pavel Stehule, reviewed by Fabien Coelho

Discussion: https://postgr.es/m/CAFj8pRBhYVvO34FU=EKb=nAF5t3b++krKt1FneCmR0kuF5m-QA@mail.gmail.com

1 files changed, 2 insertions, 1 deletions

diff --git a/src/bin/psql/help.c b/src/bin/psql/help.c
index 9d366180af5..4d1c0ec3c68 100644
--- a/src/bin/psql/help.c
+++ b/src/bin/psql/help.c
@@ -167,13 +167,14 @@ slashUsage(unsigned short int pager)
 	 * Use "psql --help=commands | wc" to count correctly.  It's okay to count
 	 * the USE_READLINE line even in builds without that.
 	 */
-	output = PageOutput(122, pager ? &(pset.popt.topt) : NULL);
+	output = PageOutput(125, pager ? &(pset.popt.topt) : NULL);
 
 	fprintf(output, _("General\n"));
 	fprintf(output, _("  \\copyright             show PostgreSQL usage and distribution terms\n"));
 	fprintf(output, _("  \\crosstabview [COLUMNS] execute query and display results in crosstab\n"));
 	fprintf(output, _("  \\errverbose            show most recent error message at maximum verbosity\n"));
 	fprintf(output, _("  \\g [FILE] or ;         execute query (and send results to file or |pipe)\n"));
+	fprintf(output, _("  \\gdesc                 describe result of query, without executing it\n"));
 	fprintf(output, _("  \\gexec                 execute query, then execute each value in its result\n"));
 	fprintf(output, _("  \\gset [PREFIX]         execute query and store results in psql variables\n"));
 	fprintf(output, _("  \\gx [FILE]             as \\g, but forces expanded output mode\n"));