How can I convert a string to a double precision in PostgreSQL?

Question

How can I convert a string to a double precision in PostgreSQL ?

I tried something like :

update points set latitude2 = cast(latitude as double) ;

where latitude is a string and latitude2 is a double. I just can't get it to work.

"can't get it to work" is not a valid Postgres error message. Please post the complete error (or describe what exactly isn't working)

Jack Douglas · Answer 1 · 2011-07-11 09:13:06Z

double is not a postgres data type:

select cast('324342' as double);
ERROR:  type "double" does not exist

but double precision is:

select cast('132342' as double precision);

 float8
--------
 132342
(1 row)

So try:

update points set latitude2 = cast(latitude as double precision) ;

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