SQL 如何将列类型从 varchar 转换为 PostgreSQL 中的日期？
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How to convert column type from varchar to date in PostgreSQL?
提问by chandrasekhar
I have varchardata type column and datedata type column.
我有varchar数据类型列和date数据类型列。
I have to update varcharcolumn data into datecolumn in PostgreSQL.
我必须将varchar列数据更新为datePostgreSQL 中的列。
Is it possible?
是否可以？
Thanks.
谢谢。
回答by Alexander Monteiro
ALTER TABLE <tablename> ALTER COLUMN <columnname> TYPE DATE
using to_date(<columnname>, 'YYYY-MM-DD');
回答by Salil
UPDATE tableName SET dateColumn=to_date(varcharColumn, 'DD MM YYYY')
Assuming you are saving "07 04 2010"
假设您正在保存“07 04 2010”
You can find further examples and explanation in the documentation:
您可以在文档中找到更多示例和说明：
http://www.postgresql.org/docs/current/interactive/functions-formatting.html
http://www.postgresql.org/docs/current/interactive/functions-formatting.html
回答by MJB
to_date('05 Dec 2000', 'DD Mon YYYY')
回答by Satish
syntax for typecasting:
类型转换的语法：
alter table table_name alter column_name
type converting_data_type using(column_name::converting_data_type)
converting from varchar to date
从 varchar 转换为日期
alter table table_name
alter column_name type date using(column_name::date)
