```
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
public void testSubquerySpacing() {
        assertEquals(statement("explain [ explain [ from a ] | where b == 1 ]"), statement("explain[explain[from a]|where b==1]"));
    }
    public void testBlockComments() {
        String query = " explain [ from foo ] | limit 10 ";
        LogicalPlan expected = statement(query);
        int wsIndex = query.indexOf(' ');
        do {
            String queryWithComment = query.substring(0, wsIndex)
                + "/*explain [ \nfrom bar ] | where a > b*/"
                + query.substring(wsIndex + 1);
            assertEquals(expected, statement(queryWithComment));
            wsIndex = query.indexOf(' ', wsIndex + 1);
        } while (wsIndex >= 0);
    }
    public void testSingleLineComments() {
        String query = " explain [ from foo ] | limit 10 ";
        LogicalPlan expected = statement(query);
        int wsIndex = query.indexOf(' ');
        do {
            String queryWithComment = query.substring(0, wsIndex)
                + "//explain [ from bar ] | where a > b \n"
                + query.substring(wsIndex + 1);
            assertEquals(expected, statement(queryWithComment));
            wsIndex = query.indexOf(' ', wsIndex + 1);
        } while (wsIndex >= 0);
    }
    public void testNewLines() {
        String[] delims = new String[] { "", "\r", "\n", "\r\n" };
        Function<String, String> queryFun = d -> d + "from " + d + " foo " + d + "| eval " + d + " x = concat(bar, \"baz\")" + d;