postgresql-howto-31.html

Linux初学者最好的老师就是howto了。相当于函数man。

    | <select sublist> [ ( <comma> <select sublist> )... ]

<select sublist> ::=
      <derived column>
    | <qualifier> <period> <asterisk>

<derived column> ::= <value expression> [ <as clause> ]

<as clause> ::= [ AS ] <column name>

<table expression> ::=
    <from clause>
    [ <where clause> ]
    [ <group by clause> ]
    [ <having clause> ]

<from clause> ::= FROM <table reference>
    [ ( <comma> <table reference> )... ]

<table reference> ::=
      <table name> [ [ AS ] <correlation name>
          [ <left paren> <derived column list> <right paren> ] ]
    | <derived table> [ AS ] <correlation name>
          [ <left paren> <derived column list> <right paren> ]
    | <joined table>

<derived column list> ::= <column name list>

<derived table> ::= <table subquery>

<table subquery> ::= <subquery>

<joined table> ::=
      <cross join>
    | <qualified join>
    | <left paren> <joined table> <right paren>

<cross join> ::=
    <table reference> CROSS JOIN <table reference>

<qualified join> ::=
    <table reference> [ NATURAL ] [ <join type> ] JOIN
      <table reference> [ <join specification> ]

<join type> ::=
      INNER
    | <outer join type> [ OUTER ]
    | UNION

<outer join type> ::=
      LEFT
    | RIGHT
    | FULL

<join specification> ::=
      <join condition>
    | <named columns join>

<join condition> ::= ON <search condition>

<named columns join> ::=
    USING <left paren> <join column list> <right paren>

<join column list> ::= <column name list>

<where clause> ::= WHERE <search condition>

<group by clause> ::=
    GROUP BY <grouping column reference list>

<grouping column reference list> ::=
    <grouping column reference>
        [ ( <comma> <grouping column reference> )... ]

<grouping column reference> ::=
    <column reference> [ <collate clause> ]

<collate clause> ::= COLLATE <collation name>

<collation name> ::= <qualified name>

<having clause> ::= HAVING <search condition>

<table value constructor> ::=
    VALUES <table value constructor list>

<table value constructor list> ::=
    <row value constructor> [ ( <comma> <row value constructor> )... ]

<explicit table> ::= TABLE <table name>

<query term> ::=
      <non-join query term>
    | <joined table>

<corresponding spec> ::=
    CORRESPONDING [ BY <left paren> <corresponding column list> <right paren> ]

<corresponding column list> ::= <column name list>

<query primary> ::=
      <non-join query primary>
    | <joined table>

<case expression> ::=
      <case abbreviation>
    | <case specification>

<case abbreviation> ::=
      NULLIF <left paren> <value expression> <comma>
            <value expression> <right paren>
    | COALESCE <left paren> <value expression>
            ( <comma> <value expression> )... <right paren>

<case specification> ::=
      <simple case>
    | <searched case>

<simple case> ::=
    CASE <case operand>
      <simple when clause>...
      [ <else clause> ]
    END

<case operand> ::= <value expression>

<simple when clause> ::= WHEN <when operand> THEN <result>

<when operand> ::= <value expression>

<result> ::= <result expression> | NULL

<result expression> ::= <value expression>

<else clause> ::= ELSE <result>

<searched case> ::=
    CASE
      <searched when clause>...
      [ <else clause> ]
    END

<searched when clause> ::= WHEN <search condition> THEN <result>

<cast specification> ::=
    CAST <left paren> <cast operand> AS
        <cast target> <right paren>

<cast operand> ::=
      <value expression>
    | NULL

<cast target> ::=
      <domain name>
    | <data type>

<numeric value function> ::=
      <position expression>
    | <extract expression>
    | <length expression>

<position expression> ::=
    POSITION <left paren> <character value expression>
        IN <character value expression> <right paren>

<character value expression> ::=
      <concatenation>
    | <character factor>

<concatenation> ::=
    <character value expression> <concatenation operator>
        <character factor>

<character factor> ::=
    <character primary> [ <collate clause> ]

<character primary> ::=
      <value expression primary>
    | <string value function>

<string value function> ::=
      <character value function>
    | <bit value function>

<character value function> ::=
      <character substring function>
    | <fold>
    | <form-of-use conversion>
    | <character translation>
    | <trim function>

<character substring function> ::=
    SUBSTRING <left paren> <character value expression> FROM <start position>
                [ FOR <string length> ] <right paren>

<start position> ::= <numeric value expression>

<string length> ::= <numeric value expression>

<fold> ::= ( UPPER | LOWER )
     <left paren> <character value expression> <right paren>

<form-of-use conversion> ::=
    CONVERT <left paren> <character value expression>
        USING <form-of-use conversion name> <right paren>

<form-of-use conversion name> ::= <qualified name>

<character translation> ::=
    TRANSLATE <left paren> <character value expression>
        USING <translation name> <right paren>

<translation name> ::= <qualified name>

<trim function> ::=
    TRIM <left paren> <trim operands> <right paren>

<trim operands> ::=
    [ [ <trim specification> ] [ <trim character> ] FROM ] <trim source>

<trim specification> ::=
      LEADING
    | TRAILING
    | BOTH

<trim character> ::= <character value expression>

<trim source> ::= <character value expression>

<bit value function> ::=
    <bit substring function>

<bit substring function> ::=
    SUBSTRING <left paren> <bit value expression> FROM <start position>
        [ FOR <string length> ] <right paren>

<bit value expression> ::=
      <bit concatenation>
    | <bit factor>

<bit concatenation> ::=
    <bit value expression> <concatenation operator> <bit factor>

<bit factor> ::= <bit primary>

<bit primary> ::=
      <value expression primary>
    | <string value function>

<extract expression> ::=
    EXTRACT <left paren> <extract field>
        FROM <extract source> <right paren>

<extract field> ::=
      <datetime field>
    | <time zone field>

<datetime field> ::=
      <non-second datetime field>
    | SECOND

<time zone field> ::=
      TIMEZONE_HOUR
    | TIMEZONE_MINUTE

<extract source> ::=
      <datetime value expression>
    | <interval value expression>

<datetime value expression> ::=
      <datetime term>
    | <interval value expression> <plus sign> <datetime term>
    | <datetime value expression> <plus sign> <interval term>
    | <datetime value expression> <minus sign> <interval term>

<interval term> ::=
      <interval factor>
    | <interval term 2> <asterisk> <factor>
    | <interval term 2> <solidus> <factor>
    | <term> <asterisk> <interval factor>

<interval factor> ::=
    [ <sign> ] <interval primary>

<interval primary> ::=
      <value expression primary> [ <interval qualifier> ]

<interval term 2> ::= <interval term>

<interval value expression> ::=
      <interval term>
    | <interval value expression 1> <plus sign> <interval term 1>
    | <interval value expression 1> <minus sign> <interval term 1>
    | <left paren> <datetime value expression> <minus sign>
          <datetime term> <right paren> <interval qualifier>

<interval value expression 1> ::= <interval value expression>

<interval term 1> ::= <interval term>

<datetime term> ::=
      <datetime factor>

<datetime factor> ::=
      <datetime primary> [ <time zone> ]

<datetime primary> ::=
      <value expression primary>
    | <datetime value function>

<time zone> ::=
    AT <time zone specifier>

<time zone specifier> ::=
      LOCAL
    | TIME ZONE <interval value expression>

<length expression> ::=
      <char length expression>
    | <octet length expression>
    | <bit length expression>

<char length expression> ::=
    ( CHAR_LENGTH | CHARACTER_LENGTH )
        <left paren> <string value expression> <right paren>

<string value expression> ::=
      <character value expression>
    | <bit value expression>

<octet length expression> ::=
    OCTET_LENGTH <left paren> <string value expression> <right paren>

<bit length expression> ::=
    BIT_LENGTH <left paren> <string value expression> <right paren>

<null specification> ::=
    NULL

<default specification> ::=
    DEFAULT

<row value constructor list> ::=
    <row value constructor element>
        [ ( <comma> <row value constructor element> )... ]

<row subquery> ::= <subquery>

<comp op> ::=
      <equals operator>
    | <not equals operator>
    | <less than operator>
    | <greater than operator>
    | <less than or equals operator>
    | <greater than or equals operator>

<between predicate> ::=
    <row value constructor> [ NOT ] BETWEEN
      <row value constructor> AND <row value constructor>

<in predicate> ::=
    <row value constructor>
      [ NOT ] IN <in predicate value>

<in predicate value> ::=
      <table subquery>
    | <left paren> <in value list> <right paren>

<in value list> ::=
    <value expression> ( <comma> <value expression> )...

<like predicate> ::=
    <match value> [ NOT ] LIKE <pattern>
      [ ESCAPE <escape character> ]

<match value> ::= <character value expression>

<pattern> ::= <character value expression>

<escape character> ::= <character value expression>

<null predicate> ::= <row value constructor>
    IS [ NOT ] NULL

<quantified comparison predicate> ::=
    <row value constructor> <comp op> <quantifier> <table subquery>

<quantifier> ::= <all> | <some>

<all> ::= ALL

<some> ::= SOME | ANY

<exists predicate> ::= EXISTS <table subquery>

<unique predicate> ::= UNIQUE <table subquery>

<match predicate> ::=
    <row value constructor> MATCH [ UNIQUE ]
        [ PARTIAL | FULL ] <table subquery>

<overlaps predicate> ::=
    <row value constructor 1> OVERLAPS <row value constructor 2>

<row value constructor 1> ::= <row value constructor>

<row value constructor 2> ::= <row value constructor>

<truth value> ::=
      TRUE
    | FALSE
    | UNKNOWN

<constraint attributes> ::=
      <constraint check time> [ [ NOT ] DEFERRABLE ]
    | [ NOT ] DEFERRABLE [ <constraint check time> ]

<constraint check time> ::=
      INITIALLY DEFERRED
    | INITIALLY IMMEDIATE

<table constraint definition> ::=
    [ <constraint name definition> ]
    <table constraint> [ <constraint attributes> ]

<table constraint> ::=
      <unique constraint definition>
    | <referential constraint definition>
    | <check constraint definition>

<unique constraint definition> ::=
            <unique specification> even in SQL3)
    <unique specification>
      <left paren> <unique column list> <right paren>

<unique column list> ::= <column name list>

<referential constraint definition> ::=
    FOREIGN KEY
        <left paren> <referencing columns> <right paren>
      <references specification>

<referencing columns> ::=
    <reference column list>

<module contents> ::=
      <declare cursor>
    | <dynamic declare cursor>
    | <procedure>

<declare cursor> ::=
    DECLARE <cursor name> [ INSENSITIVE ] [ SCROLL ] CURSOR
      FOR <cursor specification>

<cursor name> ::= <identifier>

<cursor specification> ::=
    <query expression> [ <order by clause> ]
      [ <updatability clause> ]