Is it the string delimiter that's the issue here? To embed single quotes in a string, use double quote on the extremes of the string.
const indicatorsSource = new carto.source.SQL("
SELECT *
FROM indicators WHERE grain ILIKE 'Yes'
");
However I don't know of a 'grain' named 'Yes'. Grains are wheat, rye, oat. Oh, and now that I think about it... where's the wildcard that LIKE and ILIKE are supposed to use? Getting grain starting with 'w' would be this
const indicatorsSource = new carto.source.SQL("
SELECT *
FROM indicators WHERE grain ILIKE 'w%'
");
Is that more what you're looking for?
HTH,
Mike