Fix(doris): postgres interval type date function

[Toms1999]

Before you file an issue

• Make sure you specify the "read" dialect eg. parse_one(sql, read="postgres")
• Make sure you specify the "write" dialect eg. ast.sql(dialect="doris")
• Check if the issue still exists on main:Couldn't find anything related

Fully reproducible code snippet

import sqlglot

sql = """SELECT NOW() - INTERVAL '1 YEAR + 1 MONTH'"""

print(sqlglot.transpile(sql ,read="postgres" , write="doris")[0]);

output

SELECT NOW() - INTERVAL '1 YEAR + 1 MONTH'

Expected output

SELECT NOW() - INTERVAL '1' YEAR - INTERVAL '1' MONTH

import sqlglot

sql = """SELECT NOW() - INTERVAL '1 YEAR - 1 MONTH'"""

print(sqlglot.transpile(sql ,read="postgres" , write="doris")[0]);

output

SELECT NOW() - INTERVAL '1 YEAR - 1 MONTH'

Expected output

SELECT NOW() - INTERVAL '1' YEAR + INTERVAL '1' MONTH