SQLの外部結合(OUTER JOIN)

Question

表Rと表Sに対して、次のSQL文を実行した結果はどれか。

R

X	Y
A001	10
A002	20
A003	30
A005	50

S

X	Z
A002	20
A003	30
A004	40

[SQL文]
SELECT R.X AS A, R.Y AS B, S.X AS C, S.Z AS D
FROM R LEFT OUTER JOIN S ON R.X = S.X

Accepted Answer

Answer

{"type":"doc","content":[{"type":"table","content":[{"type":"tableRow","content":[{"type":"tableHeader","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":"hsl(var(--primary) / 0.15)","diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"A"}]}]},{"type":"tableHeader","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":"hsl(var(--primary) / 0.15)","diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"B"}]}]},{"type":"tableHeader","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":"hsl(var(--primary) / 0.15)","diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"C"}]}]},{"type":"tableHeader","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":"hsl(var(--primary) / 0.15)","diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"D"}]}]}]},{"type":"tableRow","content":[{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"A001"}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"10"}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"NULL"}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"NULL"}]}]}]},{"type":"tableRow","content":[{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"A005"}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"50"}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"NULL"}]}]},{"type":"tableCell","attrs":{"colspan":1,"rowspan":1,"colwidth":null,"align":null,"backgroundColor":null,"diagonalLine":null,"noBorder":false},"content":[{"type":"paragraph","attrs":{"textAlign":"left"},"content":[{"type":"text","text":"NULL"}]}]}]}]},{"type":"paragraph","attrs":{"textAlign":"left"}}]}

Answer

Answer

A	B	C	D
A001	10	NULL	NULL
A002	20	A002	20
A003	30	A003	30
NULL	NULL	A004	40
A005	50	NULL	NULL