PostgreSQL 间隔失效

Question

 select date,
    to_char(shares, '99g999g999g999') as shares,
    to_char(trades, '99g999g999') as trades,
    to_char(dollars, 'L99g999g999g999') as dollars
    from facebook
    where date >= '2017-02-01'  + interval '1 months'
    order by date;

message: ERROR:  invalid input syntax for type interval: "2017-02-01"
LINE 6:  where date >= '2017-02-01'  + interval '1 months

I know there is one way to do it by declare a date variable. so the code would be

 date >= date: 'Variable' + interval '1 month'

But I don't know how to set a date variable in PGadmin.

Answer 1

'2017-02-01' is treated as a string literal, not as a date literal. To make Postgres recognize it as a proper date value, use a proper date literal.

I prefer using ANSI date literals, which are strings prefixed with the keyword date

where date >= date '2017-02-01'  + interval '1 months'

Note that your choice of the column name date makes this quite confusing. The date on the left side refers to the column . The date prefixing the string literal refers to the data type name. To avoid the confusion, don't use reserved words (eg data types) as column names.