课后作业

课后作业/4.3.sql

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+USE SPJ;
+
+-- ①
+SELECT SNO FROM SPJ WHERE JNO='J1';
+
+-- ②
+SELECT SNO FROM SPJ WHERE JNO='J1' AND PNO='P1';
+
+-- ③
+SELECT SPJ.SNO
+FROM SPJ
+JOIN P ON SPJ.PNO = P.PNO
+WHERE SPJ.JNO = 'J1' AND P.COLOR = '红';
+
+-- ④
+SELECT SPJ.JNO
+FROM SPJ
+JOIN S ON SPJ.SNO=S.SNO
+JOIN P ON SPJ.PNO=P.PNO
+WHERE P.COLOR!='红' AND S.CITY!='天津';