update cell value in PostgreSQL

When I run the command:

su -s /bin/bash -l postgres -c "psql -d host -c 'UPDATE versi开发者_JAVA技巧on_table SET version_id='1.2' WHERE version_id=CAST ('1.1' AS character varying)'"

It worked well.

But if I changed the version_id to "1.2.1" as:

su -s /bin/bash -l postgres -c "psql -d host -c 'UPDATE version_table SET version_id='1.2.1' WHERE version_id=CAST ('1.1' AS character varying)'"

I got the following error messages:

ERROR:  syntax error at or near ".1"
LINE 1: ...M version_table WHERE version_id=CAST (1.2.1 AS char...

It seems more than one dot are not allowed.

How can I get around it?

Thank!

Add: the type of the column is character varying.

You have fighting quotes. You're using single quotes for the shell command:

psql -d host -c '...sql...'

And also for quoting strings inside the SQL:

... version_id='1.2' ...

Try using double quotes for the shell part:

psql -d host -c "UPDATE version_table SET version_id='1.2.1'  WHERE version_id=CAST ('1.1' AS character varying)"

Or put the SQL in a separate text file and feed that to psql via the standard input

psql -d host < sql_in_a_text_file.sql

change the column to some type of character datatype.