<ElementA>
    <ElementAA>false</ElementAA>
    <ElementAB>
        <SubElementB>-1</SubElementB>
        <SubElementB>2</SubElementB>
        <SubElementB>3</SubElementB>
        <SubElementB>-4</SubElementB>
    </ElementAB>
    <ElementAC>Some text for element AC</ElementAC>
</ElementA>

select
    m.c.value('(ElementAA/.)[1]', 'bit') as ElementAA,
    m.c.value('(ElementAB/.)[1]', 'nvarchar(max)') as ElementAB,
    m.c.value('(ElementAC/.)[1]', 'nvarchar(max)') as ElementAC
from
    sqm as s
cross apply
    s.data.nodes('Sqm/ElementA') as m(c)

ElementAA | ElementAB | ElementAC
false     | -123-4    | Some text for element AC

ElementAA | ElementAB   | ElementAC
false     | -1,2,3,-4   | Some text for element AC

╔═══════════╦═══════════╦══════════════════════════╗
║ ElementAA ║ ElementAB ║        ElementAC         ║
╠═══════════╬═══════════╬══════════════════════════╣
║         0 ║ -1,2,3,-4 ║ Some text for element AC ║
╚═══════════╩═══════════╩══════════════════════════╝