```
ROW a="b c d"
| DISSECT a "%{b} %{} %{d}"
```
returns

```
       a       |       b       |               |       d       
---------------+---------------+---------------+---------------
b c d          |b              |null           |d 
```

it should ignore the empty pattern instead, and only return `a, b, d`
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/parser/StatementParserTests.java
LogicalPlan reference = statement(queryFun.apply(delims[0]));
        for (int i = 1; i < delims.length; i++) {
            LogicalPlan candidate = statement(queryFun.apply(delims[i]));
            assertThat(candidate, equalTo(reference));
        }
    }
    public void testSuggestAvailableSourceCommandsOnParsingError() {
        for (Tuple<String, String> queryWithUnexpectedCmd : List.of(
            Tuple.tuple("frm foo", "frm"),
            Tuple.tuple("expln[from bar]", "expln"),
            Tuple.tuple("not-a-thing logs", "not-a-thing"),
            Tuple.tuple("high5 a", "high5"),
            Tuple.tuple("a+b = c", "a+b"),
            Tuple.tuple("a//hi", "a"),
            Tuple.tuple("a/*hi*/", "a"),
            Tuple.tuple("explain [ frm a ]", "frm")
        )) {
            ParsingException pe = expectThrows(ParsingException.class, () -> statement(queryWithUnexpectedCmd.v1()));
            assertThat(
                pe.getMessage(),
                allOf(
                    containsString("mismatched input '" + queryWithUnexpectedCmd.v2() + "'"),
                    containsString("'explain'"),
                    containsString("'from'"),
                    containsString("'row'")
                )
            );
        }
    }
    public void testSuggestAvailableProcessingCommandsOnParsingError() {