```
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
"<logstash-{now/M{yyyy.MM}}>,<logstash-{now/d{yyyy.MM.dd|+12:00}}>",
            "from <logstash-{now/M{yyyy.MM}}>, `<logstash-{now/d{yyyy.MM.dd|+12:00}}>`"
        );
    }
    public void testIdentifierAsFieldName() {
        String[] operators = new String[] { "==", "!=", ">", "<", ">=", "<=" };
        Class<?>[] expectedOperators = new Class<?>[] {
            Equals.class,
            Not.class,
            GreaterThan.class,
            LessThan.class,
            GreaterThanOrEqual.class,
            LessThanOrEqual.class };
        String[] identifiers = new String[] { "abc", "`abc`", "ab_c", "a.b.c", "@a", "a.@b", "`a@b.c`" };
        String[] expectedIdentifiers = new String[] { "abc", "abc", "ab_c", "a.b.c", "@a", "a.@b", "a@b.c" };
        LogicalPlan where;
        for (int i = 0; i < operators.length; i++) {
            for (int j = 0; j < identifiers.length; j++) {
                where = processingCommand("where " + identifiers[j] + operators[i] + "123");
                assertThat(where, instanceOf(Filter.class));
                Filter filter = (Filter) where;
                assertThat(filter.children().size(), equalTo(1));
                assertThat(filter.condition(), instanceOf(expectedOperators[i]));
                BinaryComparison comparison;
                if (filter.condition() instanceof Not not) {
                    assertThat(not.children().get(0), instanceOf(Equals.class));
                    comparison = (BinaryComparison) (not.children().get(0));
                } else {
                    comparison = (BinaryComparison) filter.condition();
                }