甚至根据@vkkeeper的响应进行了更多的修改。增加了从特定模式查询表的可能性。

CREATE OR REPLACE FUNCTION public.describe_table(p_schema_name character varying, p_table_name character varying)
  RETURNS SETOF text AS
$BODY$
DECLARE
    v_table_ddl   text;
    column_record record;
    table_rec record;
    constraint_rec record;
    firstrec boolean;
BEGIN
    FOR table_rec IN
        SELECT c.relname, c.oid FROM pg_catalog.pg_class c
            LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
                WHERE relkind = 'r'
                AND n.nspname = p_schema_name
                AND relname~ ('^('||p_table_name||')$')
          ORDER BY c.relname
    LOOP
        FOR column_record IN
            SELECT
                b.nspname as schema_name,
                b.relname as table_name,
                a.attname as column_name,
                pg_catalog.format_type(a.atttypid, a.atttypmod) as column_type,
                CASE WHEN
                    (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                     FROM pg_catalog.pg_attrdef d
                     WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef) IS NOT NULL THEN
                    'DEFAULT '|| (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                                  FROM pg_catalog.pg_attrdef d
                                  WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)
                ELSE
                    ''
                END as column_default_value,
                CASE WHEN a.attnotnull = true THEN
                    'NOT NULL'
                ELSE
                    'NULL'
                END as column_not_null,
                a.attnum as attnum,
                e.max_attnum as max_attnum
            FROM
                pg_catalog.pg_attribute a
                INNER JOIN
                 (SELECT c.oid,
                    n.nspname,
                    c.relname
                  FROM pg_catalog.pg_class c
                       LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
                  WHERE c.oid = table_rec.oid
                  ORDER BY 2, 3) b
                ON a.attrelid = b.oid
                INNER JOIN
                 (SELECT
                      a.attrelid,
                      max(a.attnum) as max_attnum
                  FROM pg_catalog.pg_attribute a
                  WHERE a.attnum > 0
                    AND NOT a.attisdropped
                  GROUP BY a.attrelid) e
                ON a.attrelid=e.attrelid
            WHERE a.attnum > 0
              AND NOT a.attisdropped
            ORDER BY a.attnum
        LOOP
            IF column_record.attnum = 1 THEN
                v_table_ddl:='CREATE TABLE '||column_record.schema_name||'.'||column_record.table_name||' (';
            ELSE
                v_table_ddl:=v_table_ddl||',';
            END IF;

            IF column_record.attnum <= column_record.max_attnum THEN
                v_table_ddl:=v_table_ddl||chr(10)||
                         '    '||column_record.column_name||' '||column_record.column_type||' '||column_record.column_default_value||' '||column_record.column_not_null;
            END IF;
        END LOOP;

        firstrec := TRUE;
        FOR constraint_rec IN
            SELECT conname, pg_get_constraintdef(c.oid) as constrainddef
                FROM pg_constraint c
                    WHERE conrelid=(
                        SELECT attrelid FROM pg_attribute
                        WHERE attrelid = (
                            SELECT oid FROM pg_class WHERE relname = table_rec.relname
                                AND relnamespace = (SELECT ns.oid FROM pg_namespace ns WHERE ns.nspname = p_schema_name)
                        ) AND attname='tableoid'
                    )
        LOOP
            v_table_ddl:=v_table_ddl||','||chr(10);
            v_table_ddl:=v_table_ddl||'CONSTRAINT '||constraint_rec.conname;
            v_table_ddl:=v_table_ddl||chr(10)||'    '||constraint_rec.constrainddef;
            firstrec := FALSE;
        END LOOP;
        v_table_ddl:=v_table_ddl||');';
        RETURN NEXT v_table_ddl;
    END LOOP;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

pg_dump -t 'schema-name.table-name' --schema-only database-name

更多信息-在手册。

从linux命令行在postgresql中为一个表生成create table语句:

为演示创建一个表:

CREATE TABLE your_table(
    thekey   integer NOT NULL,  
    ticker   character varying(10) NOT NULL,
    date_val date,
    open_val numeric(10,4) NOT NULL
); 

Pg_dump手动，可以输出表创建PSQL语句:

pg_dump -U your_user your_database -t your_table --schema-only

打印:

-- pre-requisite database and table configuration omitted
CREATE TABLE your_table (
    thekey integer NOT NULL, 
    ticker character varying(10) NOT NULL, 
    date_val date,  
    open_val numeric(10,4) NOT NULL 
); 
-- post-requisite database and table configuration omitted
  

解释:

Pg_dump帮助我们获得关于数据库本身的信息。-U代表用户名。我的pgadmin用户没有设置密码，所以我不需要输入密码。-t选项表示指定一个表。——schema-only表示只打印关于表的数据，而不是表中的数据。

pg_dump是优秀的C代码，它试图很好地处理不断发展的sql标准，并处理在postgresql的查询语言和它在磁盘上的表示之间产生的成千上万个细节。如果你想卷自己的“psql磁盘创建语句”的安排，你是龙:https://doxygen.postgresql.org/pg__dump_8c_source.html

另一个绕过pg_dump的选项是在创建表时保存表创建SQL语句。把它放在安全的地方，需要的时候拿来。

或者使用SQL从postgresql中获取表名、列名和数据类型信息:

CREATE TABLE your_table(  thekey integer NOT NULL,
                          ticker character varying(10) NOT NULL,
                          date_val date,
                          open_val numeric(10,4) NOT NULL
); 

SELECT table_name, column_name, data_type 
FROM information_schema.columns 
WHERE table_name = 'your_table'; 

打印:

┌────────────┬─────────────┬───────────────────┐ 
│ table_name │ column_name │     data_type     │ 
├────────────┼─────────────┼───────────────────┤ 
│ your_table │ thekey      │ integer           │ 
│ your_table │ ticker      │ character varying │ 
│ your_table │ date_val    │ date              │ 
│ your_table │ open_val    │ numeric           │ 
└────────────┴─────────────┴───────────────────┘ 

这是一个有一些编辑的查询，

select 'CREATE TABLE ' || a.attrelid::regclass::text || '(' ||
string_agg(a.attname || ' ' || pg_catalog.format_type(a.atttypid, 
a.atttypmod)||
        CASE WHEN 
            (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
             FROM pg_catalog.pg_attrdef d
             WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef) IS NOT NULL THEN
            ' DEFAULT '|| (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                          FROM pg_catalog.pg_attrdef d
                          WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)
        ELSE
            '' END
||
        CASE WHEN a.attnotnull = true THEN 
            ' NOT NULL'
        ELSE
            '' END,E'\n,') || ');' 
FROM pg_catalog.pg_attribute a join pg_class on a.attrelid=pg_class.oid
WHERE a.attrelid::regclass::varchar =  
'TABLENAME_with_or_without_schema'
AND a.attnum > 0 AND NOT a.attisdropped  and pg_class.relkind='r'
group by a.attrelid;

使用它并在ddl中获得输出。出文件

~/bin/pg_dump -p 30000 -d <db_name> -U <db_user> --schema=<schema_name> -t <table_name> --schema-only >> /tmp/ddl.out

因此这将在路径:/tmp/ DDL .out中生成DDL

(注意-此解决方案不适用于PostgreSQL v12+)

我的解决方案是使用psql和-E选项登录postgres db，如下所示:

psql -E -U username -d database   

在psql中，运行以下命令查看postgres用来生成的sql 描述表语句:

-- List all tables in the schema (my example schema name is public)
\dt public.*
-- Choose a table name from above
-- For create table of one public.tablename
\d+ public.tablename  

基于运行这些描述命令后返回的sql，我能够把它们放在一起 下面是PLPGSQL函数:

CREATE OR REPLACE FUNCTION generate_create_table_statement(p_table_name varchar)
  RETURNS text AS
$BODY$
DECLARE
    v_table_ddl   text;
    column_record record;
BEGIN
    FOR column_record IN 
        SELECT 
            b.nspname as schema_name,
            b.relname as table_name,
            a.attname as column_name,
            pg_catalog.format_type(a.atttypid, a.atttypmod) as column_type,
            CASE WHEN 
                (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                 FROM pg_catalog.pg_attrdef d
                 WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef) IS NOT NULL THEN
                'DEFAULT '|| (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
                              FROM pg_catalog.pg_attrdef d
                              WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef)
            ELSE
                ''
            END as column_default_value,
            CASE WHEN a.attnotnull = true THEN 
                'NOT NULL'
            ELSE
                'NULL'
            END as column_not_null,
            a.attnum as attnum,
            e.max_attnum as max_attnum
        FROM 
            pg_catalog.pg_attribute a
            INNER JOIN 
             (SELECT c.oid,
                n.nspname,
                c.relname
              FROM pg_catalog.pg_class c
                   LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
              WHERE c.relname ~ ('^('||p_table_name||')$')
                AND pg_catalog.pg_table_is_visible(c.oid)
              ORDER BY 2, 3) b
            ON a.attrelid = b.oid
            INNER JOIN 
             (SELECT 
                  a.attrelid,
                  max(a.attnum) as max_attnum
              FROM pg_catalog.pg_attribute a
              WHERE a.attnum > 0 
                AND NOT a.attisdropped
              GROUP BY a.attrelid) e
            ON a.attrelid=e.attrelid
        WHERE a.attnum > 0 
          AND NOT a.attisdropped
        ORDER BY a.attnum
    LOOP
        IF column_record.attnum = 1 THEN
            v_table_ddl:='CREATE TABLE '||column_record.schema_name||'.'||column_record.table_name||' (';
        ELSE
            v_table_ddl:=v_table_ddl||',';
        END IF;

        IF column_record.attnum <= column_record.max_attnum THEN
            v_table_ddl:=v_table_ddl||chr(10)||
                     '    '||column_record.column_name||' '||column_record.column_type||' '||column_record.column_default_value||' '||column_record.column_not_null;
        END IF;
    END LOOP;

    v_table_ddl:=v_table_ddl||');';
    RETURN v_table_ddl;
END;
$BODY$
  LANGUAGE 'plpgsql' COST 100.0 SECURITY INVOKER;

下面是函数用法:

SELECT generate_create_table_statement('tablename');

下面是drop语句，如果你不想让这个函数永久保存:

DROP FUNCTION generate_create_table_statement(p_table_name varchar);