Знакомство с psql
Синтаксис psql
При запуске psql выводится краткая сводка четырех основных команд psql:
- \h – справка по SQL;
- \? – справка по командам psql;
- \g – выполнение запросов;
- \q – выход из psql после завершения работы.
Все команды psql начинаются с символа \ (обратная косая черта). Результат выполнения команды \? приведен в листинге 4.2.
Листинг 4.2. Получение списка команд psql booktown=# \?.
\а toggle between unaligned and aligned mode
\c[onnect] [dbname| – [user]]
connect to new database (currently 'booktown')
\C <title> table title
\copy… perform SQL COPY with data stream to the client machine
\copyright show PostgreSQL usage and distribution terms
\d <table> describe table (or view, index, sequence)
\d{t|i|s|v} list tables/indices/sequences/views
\d{p|S|l} list permissions/system tables/lobjects
\da list aggregates
\dd [object] list comment for table, type, function, or operator
\df list functions
\do list operators
\dT list data types
\e [file] edit the current query buffer or [file] with external editor
\echo <text> write text to stdout
\encoding <encoding> set client encoding
\f <sep> change field separator
\g [file] send query to backend (and results in [file] or (pipe)
\h [cmd] help on syntax of sql commands. * for all commands
\H toggle HTML mode (currently off)
\i<file> read and execute queries from <file>
\l list all databases
\lo_export. \lo_import, \lo_list. \lo_unlink
Targe object operations
\o [file] send all query results to [file], or (pipe
\p show the content of the current query buffer
\pset <opt> set table output <opt> = {format|border|expanded|fieldsep|
null|recordsep|tuples_only|title|tableattr|pagerj
\q quit psql
\qecho <text> write text to query output stream (see \o).
\r reset (clear) the query buffer
\s [file] print history or save it in [file] \set <var> <value> set internal variable
\t show only rows (currently off)
\T <tags> HTML table tags
\unset <var> unset (delete) internal variable
\w <file> write current query buffer to a <file>
\x toggle expanded output (currently off)
\z list table access permissions
\! [cmd] shell escape or command