QGIS Field calculator / Multiple CASE operator and % expression

Question

I can't seem to be able to troubleshoot my expression here. I'm trying to calculate a new field. Column "FOO_U_CODE" contains numerous 4 digit codes, the new column I want to create is a simplified version based on the first character of the code in "FOO_U_CODE".

I saw somewhere that you can use % to specify anything after one or multiple characters. Is it right?

What is wrong here?

   CASE
    WHEN "F00_U_CODE" IS'1%' THEN "Utilisatio"  = 'Residentiel'
    WHEN "F00_U_CODE" IS'2%' THEN "Utilisatio"  = 'Transports communications et services publics'
    WHEN "F00_U_CODE" IS'3%' THEN "Utilisatio"  = 'Industrielle'
    WHEN "F00_U_CODE" IS'4%' THEN "Utilisatio"  = 'Transports, communications et services publics'
    WHEN "F00_U_CODE" IS'5%' THEN "Utilisatio" =  'Commerciale'
    WHEN "F00_U_CODE" IS'6%' THEN "Utilisatio"  = 'Services'
    WHEN "F00_U_CODE" IS'7%' THEN "Utilisatio"  = 'Culturelle, recreative et loisirs'
    WHEN "F00_U_CODE" IS'8%' THEN "Utilisatio"  = 'Production et extraction des richesses naturelles'
    WHEN "F00_U_CODE" IS'9%' THEN "Utilisatio" = 'Immeubles non exploites et etendues deau'
   END

Answer 1

You should probably use LIKE instead of IS.

If "Utilisatio" is your new field, you don't have to specify it explicitely in the field calculator (just write WHEN "F00_U_CODE" LIKE '1%' THEN 'Residentiel' for instance).