在工程数据库“SPJ”中，编写SQL，在表“SPJ”插入数据，插入条件是：表“J”工程号未在表“SPJ”中出现，零件号(PNO)、供应商号(SNO)、数量(QTY)均为’S5’、’P6’、500。 ⑦编写SQL，查询至少使用三种零件的工程名称。

可以回答该问题，以下是SQL语句：

INSERT INTO SPJ (SNO, PNO, JNO, QTY)
SELECT 'S5', 'P6', J.JNO, 500
FROM J
WHERE J.JNO NOT IN (SELECT SPJ1.JNO FROM SPJ AS SPJ1 WHERE SPJ1.PNO = 'P6' AND SPJ1.SNO = 'S5')
GROUP BY J.JNO;

SELECT J.JNAME FROM J, SPJ
WHERE J.JNO = SPJ.JNO
GROUP BY J.JNO, SPJ.PNO
HAVING COUNT(DISTINCT SPJ.PNO) >= 3;