Hi, May be you think about this ?
SELECT REAL_COLUMN, *to_char(REAL_COLUMN,'9.99999EEEE') 6_significant_numbers_format *FROM TEST; Regards Tomek czw., 19 paź 2023 o 05:47 毛毛 <kr...@163.com> napisał(a): > Hi, > > Do we have a rule by follow which one can accurately info the output of a > SELECT statment FROM a table with floating-point data type? > > I am working with PostgreSQL 16 and pgAdmin 7.6. > > Here is my SQL script: > > ``` > CREATE TABLE TEST (REAL_COLUMN real); > > INSERT INTO TEST > VALUES (12345.123456789); > > SELECT * FROM TEST; > ``` > > I consulted the following doc and found that the range of real type is 6 > decimal digits precision. > > https://www.postgresql.org/docs/current/datatype-numeric.html#DATATYPE-NUMERIC > > So I thought the output of the SELECT statement should be like: 12345.1 > with 6 digits in total. > But it turns out to be 12345.123 with 8 digits in total. > May I know why would this happen? > Do we have a rule I can use to infer the correct output of a > floating-point number without running the script? > > Thank you for your time and have a great day! > >
