```
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
assertEquals(
            new Enrich(
                EMPTY,
                PROCESSING_CMD_INPUT,
                new Literal(EMPTY, "countries", KEYWORD),
                new UnresolvedAttribute(EMPTY, "country_code"),
                null,
                List.of()
            ),
            processingCommand("enrich countries ON country_code")
        );
        expectError("from a | enrich countries on foo* ", "Using wildcards (*) in ENRICH WITH projections is not allowed [foo*]");
        expectError("from a | enrich countries on foo with bar*", "Using wildcards (*) in ENRICH WITH projections is not allowed [bar*]");
        expectError(
            "from a | enrich countries on foo with x = bar* ",
            "Using wildcards (*) in ENRICH WITH projections is not allowed [bar*]"
        );
        expectError(
            "from a | enrich countries on foo with x* = bar ",
            "Using wildcards (*) in ENRICH WITH projections is not allowed [x*]"
        );
    }
    public void testMvExpand() {
        LogicalPlan cmd = processingCommand("mv_expand a");
        assertEquals(MvExpand.class, cmd.getClass());
        MvExpand expand = (MvExpand) cmd;
        assertThat(expand.target(), equalTo(attribute("a")));
    }
    public void testUsageOfProject() {
        processingCommand("project a");