i have something like this in sql:

t1.volume || ' ' || t1.vunits as volume,

t1.volume is a numeric column. it's returning:
0.59999999999999998 ml

instead of the much nicer and expected:
0.6 ml

the value of that column is actually 0.6. any idea why the process of converting to a string does that? can i avoid it? unfortunately this does not fix it:

round(t1.volume, 2) || ' ' || t1.vunits as volume,

thanks for the help.