Can I combine these two JOOQ queries into one? - sql

Question

I have two queries which look at separate database tables and find items from a JSONB column in each table that are in the format ["tag1","tag2","tag3"] etc. The purpose of the queries are to populate a list for a predictive dropdown i.e. if the list contains "dog" and the user types "d", "dog" should be returned. Each of these queries works individually and I can easily combine them into a single JOOQ query?
final Field<String> value = field(name("A", "value"), String.class);
final Result<Record1<String>> res1 = sql.dsl()
.selectDistinct(value)
.from(CAMPAIGN,lateral(table("jsonb_array_elements_text({0})", CAMPAIGN.TAGS)).as("A"))
.where(CAMPAIGN.STORE_KEY.equal(campaign.getStoreKey()))
.and(CAMPAIGN.CAMPAIGN_KEY.notEqual(campaignKey))
.and(value.like(search + "%%"))
.fetch();
final Result<Record1<String>> res2 = sql.dsl()
.selectDistinct(value)
.from(STOREFRONT, lateral(table("jsonb_array_elements_text({0})", STOREFRONT.TAGS)).as("A"))
.where(STOREFRONT.STORE_KEY.equal(campaign.getStoreKey()))
.and(value.like(search + "%%")).fetch();

Answer 1

Sure! In SQL, "combining" two queries is mostly implemented using UNION [ ALL ] (where ALL indicates that you want to maintain duplicates). In your case, write the following:
final Result<Record1<String>> result =
sql.dsl()
.select(value)
.from(
CAMPAIGN,
lateral(table("jsonb_array_elements_text({0})", CAMPAIGN.TAGS)).as("A"))
.where(CAMPAIGN.STORE_KEY.equal(campaign.getStoreKey()))
.and(CAMPAIGN.CAMPAIGN_KEY.notEqual(campaignKey))
.and(value.like(search + "%%"))
.union(
select(value)
.from(
STOREFRONT,
lateral(table("jsonb_array_elements_text({0})", STOREFRONT.TAGS)).as("A"))
.where(STOREFRONT.STORE_KEY.equal(campaign.getStoreKey()))
.and(value.like(search + "%%")))
.fetch();
Note that I have replaced selectDistinct() by select(), because the UNION operation already removes duplicates, so there's no need to remove duplicates in each individual union subquery.