psql介绍
- 通过 man psql 或者 psql --help 这两个linux 命令可以了解 psql 的用法。
postgres@pgdb-> psql --help
psql is the PostgreSQL interactive terminal.
Usage:
psql [OPTION]... [DBNAME [USERNAME]]
General options:
常用连接
-c, --command=COMMAND run only single command (SQL or internal) and exit
-d, --dbname=DBNAME database name to connect to (default: "postgres")
-f, --file=FILENAME execute commands from file, then exit
-l, --list list available databases, then exit
-v, --set=, --variable=NAME=VALUE
set psql variable NAME to VALUE
(e.g., -v ON_ERROR_STOP=1)
-V, --version output version information, then exit
-X, --no-psqlrc do not read startup file (~/.psqlrc)
-1 ("one"), --single-transaction
execute as a single transaction (if non-interactive)
-?, --help[=options] show this help, then exit
--help=commands list backslash commands, then exit
--help=variables list special variables, then exit
//输入输出选项
Input and output options:
-a, --echo-all echo all input from script
-b, --echo-errors echo failed commands
-e, --echo-queries echo commands sent to server
-E, --echo-hidden display queries that internal commands generate
-L, --log-file=FILENAME send session log to file
-n, --no-readline disable enhanced command line editing (readline)
-o, --output=FILENAME send query results to file (or |pipe)
-q, --quiet run quietly (no messages, only query output)
-s, --single-step single-step mode (confirm each query)
-S, --single-line single-line mode (end of line terminates SQL command)
//输入格式
Output format options:
-A, --no-align unaligned table output mode
-F, --field-separator=STRING
field separator for unaligned output (default: "|")
-H, --html HTML table output mode
-P, --pset=VAR[=ARG] set printing option VAR to ARG (see \pset command)
-R, --record-separator=STRING
record separator for unaligned output (default: newline)
-t, --tuples-only print rows only
-T, --table-attr=TEXT set HTML table tag attributes (e.g., width, border)
-x, --expanded turn on expanded table output
-z, --field-separator-zero
set field separator for unaligned output to zero byte
-0, --record-separator-zero
set record separator for unaligned output to zero byte
//连接选项
Connection options:
-h, --host=HOSTNAME database server host or socket directory (default: "/home/postgres/pgdata")
-p, --port=PORT database server port (default: "1921")
-U, --username=USERNAME database user name (default: "postgres")
-w, --no-password never prompt for password
-W, --password force password prompt (should happen automatically)
For more information, type "\?" (for internal commands) or "\help" (for SQL
commands) from within psql, or consult the psql section in the PostgreSQL
documentation.
Report bugs to <pgsql-bugs@postgresql.org>.
也可以用man psql 命令：
ostgres@pgdb-> man psql
PSQL(1) PostgreSQL 9.5.3 Documentation PSQL(1)
NAME
psql - PostgreSQL interactive terminal
SYNOPSIS
psql [option...] [dbname [username]]
DESCRIPTION
psql is a terminal-based front-end to PostgreSQL. It enables you to type in queries interactively,
issue them to PostgreSQL, and see the query results. Alternatively, input can be from a file. In
addition, it provides a number of meta-commands and various shell-like features to facilitate writing
scripts and automating a wide variety of tasks.
OPTIONS
-a
--echo-all
Print all nonempty input lines to standard output as they are read. (This does not apply to lines
read interactively.) This is equivalent to setting the variable ECHO to all.
-A
--no-align
Switches to unaligned output mode. (The default output mode is otherwise aligned.)
-b
--echo-errors
Print failed SQL commands to standard error output. This is equivalent to setting the variable
ECHO to errors.
-c command
--command=command
Specifies that psql is to execute one command string, command, and then exit. This is useful in
shell scripts. Start-up files (psqlrc and ~/.psqlrc) are ignored with this option.
command must be either a command string that is completely parsable by the server (i.e., it
contains no psql-specific features), or a single backslash command. Thus you cannot mix SQL and
psql meta-commands with this option. To achieve that, you could pipe the string into psql, for
example: echo '\x \\ SELECT * FROM foo;' | psql. (\\ is the separator meta-command.)
进入到psql后的常用技巧
无论是通过 unix-socket-domain 还是TCP-IP方式连接进入psql后， 就意味着可以使用sql语句操作数据库了。
- 按tab键自动补齐
postgres=# create
//此时通过使用tab键，就可以补齐命令，如下
AGGREGATE EXTENSION MATERIALIZED VIEW SERVER UNIQUE
CAST FOREIGN DATA WRAPPER OPERATOR TABLE UNLOGGED
COLLATION FOREIGN TABLE POLICY TABLESPACE USER
CONVERSION FUNCTION ROLE TEMP USER MAPPING FOR
DATABASE GROUP RULE TEXT SEARCH VIEW
DOMAIN INDEX SCHEMA TRIGGER
EVENT TRIGGER LANGUAGE SEQUENCE TYPE
postgres=# create tab
按“tab”键也可以自动补齐喔-
postgres=# create tab
- 帮助命令：
// 通过 \h 可以显示 create table 的语法
postgres=# \h create table
Command: CREATE TABLE
Description: define a new table
Syntax:
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name ( [
{ column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ]
| table_constraint
| LIKE source_table [ like_option ... ] }
[, ... ]
] )
[ INHERITS ( parent_table [, ... ] ) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name
OF type_name [ (
{ column_name WITH OPTIONS [ column_constraint [ ... ] ]
| table_constraint }
[, ... ]
) ]
[ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ]
[ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ]
[ TABLESPACE tablespace_name ]
where column_constraint is:
[ CONSTRAINT constraint_name ]
{ NOT NULL |
NULL |
CHECK ( expression ) [ NO INHERIT ] |
DEFAULT default_expr |
UNIQUE index_parameters |
PRIMARY KEY index_parameters |
//通过 \? 命令可以列出一些快捷命令：
postgres=# \?
General
\copyright show PostgreSQL usage and distribution terms
\g [FILE] or ; execute query (and send results to file or |pipe)
\gset [PREFIX] execute query and store results in psql variables
\q quit psql
\watch [SEC] execute query every SEC seconds
Help
\? [commands] show help on backslash commands
\? options show help on psql command-line options
\? variables show help on special variables
\h [NAME] help on syntax of SQL commands, * for all commands
Query Buffer
\e [FILE] [LINE] edit the query buffer (or file) with external editor
\ef [FUNCNAME [LINE]] edit function definition with external editor
\p show the contents of the query buffer
\r reset (clear) the query buffer
\s [FILE] display history or save it to file
\w FILE write query buffer to file
Input/Output
\copy ... perform SQL COPY with data stream to the client host
\echo [STRING] write string to standard output
\i FILE execute commands from file
\ir FILE as \i, but relative to location of current script
\o [FILE] send all query results to file or |pipe
\qecho [STRING] write string to query output stream (see \o)
Informational 用法
(options: S = show system objects, + = additional detail)
\d[S+] list tables, views, and sequences
\d[S+] NAME describe table, view, sequence, or index
\da[S] [PATTERN] list aggregates
\db[+] [PATTERN] list tablespaces
\dc[S+] [PATTERN] list conversions
\dC[+] [PATTERN] list casts
\dd[S] [PATTERN] show object descriptions not displayed elsewhere
\ddp [PATTERN] list default privi
- \set VERBOSITY verbose
设置详细的打印输出, 例如可以报出问题的代码
postgres=# \set VERBOSITY verbose
postgres=# select a ;
ERROR: 42703: column "a" does not exist
LINE 1: select a ;
^
//说明这个报错是通过 parse_relation.c 文件的 3090行爆出来的。
也就是errorMissingColumn函数报的错误
LOCATION: errorMissingColumn, parse_relation.c:3090
