Converting from one date format to another using DB Browser for SQLite

Question

I am looking to convert one date format to another using SQL. I am using DB Browser for SQLite and the dates are stored in a column of type \'TEXT\'.

Here are 2 examples

Answer 1

So I don't know much about python so had to go with the 'obscene chain of instr() and substr() commands'. It's a mess, but it seems to work now.

instr(DATE,'/') used to find the position of the first '/'

length (rtrim(DATE, 'PMA0123456789: ')) used to find the position of the second '/'

instr(DATE, ':') used to find the position of the first ':'

Well below is the mess I created :D

UPDATE testtable
SET DATE = 
substr (DATE, length (rtrim(DATE, 'PMA0123456789: '))+1,4) || '-' ||
CASE instr(DATE, '/')
    WHEN 2 THEN
        '0' 
    ELSE ''
END 
|| substr (DATE,1,instr(DATE,'/')-1) || '-' ||
CASE (length (rtrim(DATE, 'PMA0123456789: '))) - instr(DATE,'/')
    WHEN 2 THEN
        '0' 
    ELSE '' 
END 
|| substr (DATE,instr(DATE,'/')+1, length (rtrim(DATE, 'PMA0123456789: ')) - instr(DATE,'/')-1)
|| ' ' || 
CASE substr(DATE,length(DATE)-1,2)
    WHEN 'AM' THEN
        CASE substr(DATE, instr(DATE, ':')-2,2)
            WHEN '12' then
                '00'
            ELSE
                CASE substr(DATE, instr(DATE, ':')-2, 1)
                    WHEN ' ' THEN 
                        '0'
                    ELSE
                        substr(DATE, instr(DATE, ':')-2,1)  
                END
                || substr(DATE, instr(DATE, ':')-1,1) 
        END
    WHEN 'PM' THEN
        CASE substr(DATE, instr(DATE, ':')-2,2) 
            WHEN '12' THEN
                substr(DATE, instr(DATE, ':')-2,2) 
            ELSE
                CAST (substr(DATE,instr(DATE, ':')-2,2) AS INT) + 12 
        END
    ELSE
        'error'
END 
|| ':' || substr(DATE,instr(DATE, ':')+1,5);