PostgreSQL queries containing, for example, single quotes or semicolons need to be escaped.

This won’t work:

UPDATE jobs SET work=':'';

To make it work, escape the strings using C-style escapes (E’’) and replacing single-quotes with ‘’:

UPDATE jobs SET work=E':''';

See section “4.1.2.2. String Constants with C-style Escapes” in the PostgreSQL documentation https://www.postgresql.org/docs/10/sql-syntax-lexical.html for details.