在 Postgres 中创建 table 时将空列设置为带时区的时间戳
Setting an empty column as a timestamp with time zone when creating a table in Postgres
我正在尝试创建一个 table,它有一个名为 decay_date
的列,该列将具有空值(暂时)但被格式化为具有时区数据类型的时间戳。如果我只是这样做:
CREATE TABLE my_schema.final_summed_table AS
SELECT
'Unstudied' AS table_name,
r.region,
r.state,
r.co_fips,
c.co_name AS county,
'TIER 0' AS tiermetric_lfd,
'UNASSESSED' AS val_combine_lfd,
'Unmapped' AS mod_unmod_lfd,
'' AS det_approx_lfd,
'' AS decay_date_lfd TYPE TIMESTAMP WITH TIME ZONE NULL USING decay_date_lfd::TIMESTAMP
FROM my_schema.unmapped r, cnms.counties c
WHERE r.co_fips = c.co_fips
我得到一个错误:Syntax error near 'TYPE'
此 table 稍后将与另一个 table 具有相同的 decay_date
列,数据类型为 timestamp with time zone .如何在创建 table 时为我的 decay_date
列设置时间戳数据类型?
''
不是开始时间戳的有效值。而且您不能像在列别名中那样使用 USING
。只有当您 ALTER
a table 并更改列的类型时才允许(并且需要)。
只需 select 一个 null
值并将其转换为所需的类型:
null::timestamptz AS decay_date_lfd
这是错误的语法。您必须将文字转换为所需的类型。
所以使用 NULL 值:
CREATE TABLE my_schema.final_summed_table AS
SELECT
CAST ('Unstudied' AS text) AS table_name,
r.region,
r.state,
r.co_fips,
c.co_name AS county,
CAST ('TIER 0' AS text) AS tiermetric_lfd,
CAST ('UNASSESSED' AS text) AS val_combine_lfd,
CAST ('Unmapped' AS text) AS mod_unmod_lfd,
CAST (NULL AS text) AS det_approx_lfd,
CAST (decay_date_lfd AS timestamp with time zone) AS decay_date_lfd
FROM my_schema.unmapped r, cnms.counties c
WHERE r.co_fips = c.co_fips;
我会避免使用 CREATE TABLE ... AS
,而是使用 CREATE TABLE
和 INSERT INTO ... SELECT ...
。
我正在尝试创建一个 table,它有一个名为 decay_date
的列,该列将具有空值(暂时)但被格式化为具有时区数据类型的时间戳。如果我只是这样做:
CREATE TABLE my_schema.final_summed_table AS
SELECT
'Unstudied' AS table_name,
r.region,
r.state,
r.co_fips,
c.co_name AS county,
'TIER 0' AS tiermetric_lfd,
'UNASSESSED' AS val_combine_lfd,
'Unmapped' AS mod_unmod_lfd,
'' AS det_approx_lfd,
'' AS decay_date_lfd TYPE TIMESTAMP WITH TIME ZONE NULL USING decay_date_lfd::TIMESTAMP
FROM my_schema.unmapped r, cnms.counties c
WHERE r.co_fips = c.co_fips
我得到一个错误:Syntax error near 'TYPE'
此 table 稍后将与另一个 table 具有相同的 decay_date
列,数据类型为 timestamp with time zone .如何在创建 table 时为我的 decay_date
列设置时间戳数据类型?
''
不是开始时间戳的有效值。而且您不能像在列别名中那样使用 USING
。只有当您 ALTER
a table 并更改列的类型时才允许(并且需要)。
只需 select 一个 null
值并将其转换为所需的类型:
null::timestamptz AS decay_date_lfd
这是错误的语法。您必须将文字转换为所需的类型。
所以使用 NULL 值:
CREATE TABLE my_schema.final_summed_table AS
SELECT
CAST ('Unstudied' AS text) AS table_name,
r.region,
r.state,
r.co_fips,
c.co_name AS county,
CAST ('TIER 0' AS text) AS tiermetric_lfd,
CAST ('UNASSESSED' AS text) AS val_combine_lfd,
CAST ('Unmapped' AS text) AS mod_unmod_lfd,
CAST (NULL AS text) AS det_approx_lfd,
CAST (decay_date_lfd AS timestamp with time zone) AS decay_date_lfd
FROM my_schema.unmapped r, cnms.counties c
WHERE r.co_fips = c.co_fips;
我会避免使用 CREATE TABLE ... AS
,而是使用 CREATE TABLE
和 INSERT INTO ... SELECT ...
。