Sqlite: convert semicolon separated positive values to negative values

Question

I have a SQLite table that look like this:

name	value
Julia	43
Julia	12;54
Julia	10;7;32
Julia	NULL
Julia	11;42

So my aim is to multiply all values in the column value by -1. When I run something like this:

UPDATE table
SET value = value * -1
WHERE name = 'Julia' 
  AND value IS NOT NULL;

this leads to this table:

name	value
Julia	-43
Julia	-12
Julia	-10
Julia	NULL
Julia	-11

The second and third semicolon separated values are lost. But the output table should look like this one:

name	value
Julia	-43
Julia	-12;-54
Julia	-10;-7;-32
Julia	NULL
Julia	-11;-42

Answer 1

For this sample data you can replace all occurrences of ';' with ';-' and concatenate a '-' at the beginning of value:

UPDATE tablename
SET value = '-' || REPLACE(value, ';', ';-')
WHERE name = 'Julia' AND value IS NOT NULL;

See the demo.