diff --git a/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt b/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
index a4afe62b6d..7ef03a7bfc 100644
--- a/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
+++ b/jOOQ-manual/src/main/resources/org/jooq/web/grammar-3.12.txt
@@ -974,7 +974,19 @@ timeLiteral = 'TIME' stringLiteral
 timestampLiteral = 'TIMESTAMP' stringLiteral
 ;
 
-intervalLiteral = 'INTERVAL' stringLiteral
+intervalLiteral =
+  'INTERVAL' stringLiteral
+| field
+  (
+    ( 'YEAR' | 'YEARS' )
+  | ( 'MONTH' | 'MONTHS' )
+  | ( 'DAY' | 'DAYS' )
+  | ( 'HOUR' | 'HOURS' )
+  | ( 'MINUTE' | 'MINUTES' )
+  | ( 'SECOND' | 'SECONDS' )
+  | ( 'MILLISECOND' | 'MILLISECONDS' )
+  | ( 'MICROSECOND' | 'MICROSECONDS' )
+  )
 ;
 
 signedInteger = todo
diff --git a/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java b/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
index ff80af9e05..bb5de8f8b4 100644
--- a/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/ParserImpl.java
@@ -4326,15 +4326,48 @@ final class ParserImpl implements Parser {
         if (N.is(type) && r instanceof Field)
             for (;;)
                 if (parseIf(ctx, '+'))
-                    r = ((Field) r).add((Field) parseFactor(ctx, type));
+                    r = parseSumRightOperand(ctx, type, r, true);
                 else if (parseIf(ctx, '-'))
-                    r = ((Field) r).sub((Field) parseFactor(ctx, type));
+                    r = parseSumRightOperand(ctx, type, r, false);
                 else
                     break;
 
         return r;
     }
 
+    private static final Field parseSumRightOperand(ParserContext ctx, Type type, FieldOrRow r, boolean add) {
+        Field f = (Field) parseFactor(ctx, type);
+        DatePart part;
+
+        if ((parseKeywordIf(ctx, "YEAR") || parseKeywordIf(ctx, "YEARS")) && ctx.requireProEdition())
+            part = DatePart.YEAR;
+        else if ((parseKeywordIf(ctx, "MONTH") || parseKeywordIf(ctx, "MONTHS")) && ctx.requireProEdition())
+            part = DatePart.MONTH;
+        else if ((parseKeywordIf(ctx, "DAY") || parseKeywordIf(ctx, "DAYS")) && ctx.requireProEdition())
+            part = DatePart.DAY;
+        else if ((parseKeywordIf(ctx, "HOUR") || parseKeywordIf(ctx, "HOURS")) && ctx.requireProEdition())
+            part = DatePart.HOUR;
+        else if ((parseKeywordIf(ctx, "MINUTE") || parseKeywordIf(ctx, "MINUTES")) && ctx.requireProEdition())
+            part = DatePart.MINUTE;
+        else if ((parseKeywordIf(ctx, "SECOND") || parseKeywordIf(ctx, "SECONDS")) && ctx.requireProEdition())
+            part = DatePart.SECOND;
+        else
+            part = null;
+
+
+
+
+
+
+
+
+
+            if (add)
+                return ((Field) r).add(f);
+            else
+                return ((Field) r).sub(f);
+    }
+
     private static final FieldOrRow parseFactor(ParserContext ctx, Type type) {
         FieldOrRow r = parseExp(ctx, type);