Here are two methods for returning the Julian Day in SQLite.

The Julian Day is the fractional number of days since noon in Greenwich on November 24, 4714 B.C. It’s the continuous count of days since the beginning of the Julian period, and is used primarily by astronomers, and in software for easily calculating elapsed days between two events.

Option 1: The JulianDay() Function

The JulianDay() function is designed specifically for returning the Julian Day based on a given date. Therefore, we can do the following:

SELECT JulianDay('now');

Result:

2459648.53799336

The return value is numeric.

Option 2: The StrfTime() Function

The StrfTime() function can also be used for returning the Julian Day:

SELECT StrfTime('%J', 'now');

Result:

2459648.541693287

This function returns a text representation of the numeric value.

Combined

Here are the functions combined into a single SELECT statement:

SELECT 
    JulianDay('now') AS JulianDay,
    StrfTime('%J', 'now') AS StrfTime;

Result:

JulianDay         StrfTime         
----------------  -----------------
2459648.54331729  2459648.543317292