[postgis-users] Finding the min point point along an line and ST_Line_Substring

[dave.potts at pinan.co.uk]

I have a line string  geometry,  I am trying to find the min point between
the start and end point of this line

Can I use st_Line_substring(foo,0.5,0.5) to return the min point ?

Are there any pit falls I should be aware of ?