¡¤9¡¤ When Grade between 90 and 100 THEN Grade = 'ÓÅ' When Grade between 80 and 89 THEN Grade = 'Á¼' When Grade between 70 and 79 THEN Grade = 'ÖÐ' When Grade between 60 and 69 THEN Grade = '¼°¸ñ' Else Grade = '²»¼°¸ñ' End C. Case
When Grade between 90 and 100 THEN 'ÓÅ' When Grade between 80 and 89 THEN 'Á¼' When Grade between 70 and 79 THEN 'ÖÐ' When Grade between 60 and 69 THEN '¼°¸ñ' Else '²»¼°¸ñ' End
D. Case Grade
When 90~100 THEN Grade = 'ÓÅ' When 80~89 THEN Grade = 'Á¼' When 70~79 THEN Grade = 'ÖÐ' When 60~69 THEN Grade = '¼°¸ñ' Else Grade = '²»¼°¸ñ'
End
8£®ÏÂÊöÓï¾äµÄ¹¦ÄÜÊǽ«Á½¸ö²éѯ½á¹ûºÏ²¢ÎªÒ»¸ö½á¹û¡£ÆäÖÐÕýÈ·µÄÊÇ B
A£®select sno,sname,sage from student where sdept = 'cs' Order by sage Union
select sno,sname,sage from student where sdept = 'is' Order by sage B£®select sno,sname,sage from student where sdept = 'cs' Union
select sno,sname,sage from student where sdept = 'is' Order by sage C£®select sno,sname,sage from student where sdept = 'cs' Union
select sno,sname from student where sdept = 'is' Order by sage D£®select sno,sname,sage from student where sdept = 'cs' Order by sage Union
select sno,sname,sage from student where sdept = 'is' 9£®ÏÂÁÐSQLÓï¾äÖУ¬ÓÃÓÚÐ޸ıíÊý¾ÝµÄÓï¾äÊÇ C
A£®ALTER B£®SELECT C£®UPDATE D£®INSERT 10£®ÉèÓÐTeachers±í£¬¸Ã±íµÄ¶¨ÒåÈçÏ£º CREATE TABLE Teachers(
9
¡¤10¡¤ Tno CHAR(8) PRIMARY KEY, Tname VARCHAR(10) NOT NULL,
Age TINYINT CHECK(Age BETWEEN 25 AND 65) )
ÏÂÁвåÈëÓï¾äÖУ¬²»ÄÜÕýÈ·Ö´ÐеÄÊÇ D
A£®INSERT INTO Teachers VALUES('T100','Õźè',NULL)
B£®INSERT INTO Teachers(Tno,Tname,Age) VALUES('T100','Õźè',30) C£®INSERT INTO Teachers(Tno,Tname) VALUES('T100','Õźè') D£®INSERT INTO TeachersVALUES('T100','Õźè')
11£®ÉèÊý¾Ý¿âÖÐÒÑÓбí4-1ÖÁ4-3ËùʾµÄStudent¡¢CourseºÍSC±í¡£ÏÖÒª²éѯѧÉúÑ¡µÄµÚ2ѧÆÚ¿ªÉè¿Î³ÌµÄÇé¿ö£¬Ö»ÐèÁгöѧºÅ¡¢ÐÕÃû¡¢ËùÔÚϵºÍËùÑ¡µÄ¿Î³ÌºÅ¡£¸Ã²éѯÉæ¼°µ½µÄ±íÊÇ D
A£®½öStudent±í B£®½öStudentºÍSC±í C£®½öStudentºÍCourse±í D£®Student¡¢SCºÍCourse±í 12£®É¾³ý¼ÆËã»úϵѧÉú£¨ÔÚstudent±íÖУ©µÄÐ޿μǼ£¨ÔÚSC±íÖУ©µÄÕýÈ·µÄÓï¾äÊDZíÊÇ B A£®DELETE FROM SC JOIN Student b ON S.Sno = b.Sno WHERE Sdept = '¼ÆËã»úϵ'
B£®DELETE FROM SC FROM SC JOIN Student b ON SC.Sno = b.Sno WHERE Sdept = '¼ÆËã»úϵ'
C£®DELETE FROM Student WHERE Sdept = '¼ÆËã»úϵ' D£®DELETE FROM SC WHERE Sdept = '¼ÆËã»úϵ'
¶þ£® Ìî¿ÕÌâ
1£® ÔÚÏà¹Ø×Ó²éѯÖУ¬×Ó²éѯµÄÖ´ÐдÎÊýÊÇÓÉ_________¾ö¶¨µÄ¡£Íâ²ã±íµÄÐÐÊý
2£® ¶Ô°üº¬»ùÓÚ¼¯ºÏ²âÊÔ×Ó²éѯµÄ²éѯÓï¾ä£¬ÊÇÏÈÖ´ÐÐ_________²ã²éѯ£¬ÔÚÖ´ÐÐ_________²ã²é
ѯ¡£ÄÚ£¬Íâ
3£® ¶Ô°üº¬Ïà¹Ø×Ó²éѯµÄ²éѯÓï¾ä£¬ÊÇÏÈÖ´ÐÐ_________²ã²éѯ£¬ÔÚÖ´ÐÐ_________²ã²éѯ¡£Í⣬
ÄÚ
4£® ¾ÛºÏº¯ÊýCOUNT(*)ÊÇ°´_________ͳ¼ÆÊý¾Ý¸öÊý¡£ÐÐ
5£® ÉèGradeÁÐÄ¿Ç°ÓÐÈý¸öÖµ£º90¡¢80ºÍNULL£¬ÔòAVG(Grade)µÄÖµÊÇ_________£¬MIN(Grade)
µÄÖµÊÇ_________¡£85£¬80
6£® ÉèÓÐѧÉú±í£¨Ñ§ºÅ£¬ÐÕÃû£¬ËùÔÚϵ£©ºÍÑ¡¿Î±í£¨Ñ§ºÅ£¬¿Î³ÌºÅ£¬³É¼¨£©£¬ÏÖÒª½¨Á¢Í³¼Æÿ¸öϵµÄ
Ñ¡¿ÎÈËÊý¡£Ç벹ȫÏÂÁÐÓï¾ä£º COUNT(DISTINCT Ñ¡¿Î±í.ѧºÅ) SELECT ËùÔÚϵ, _________ FROM Ñ¡¿Î±í JOIN ѧÉú±í ON Ñ¡¿Î±í.ѧºÅ = ѧÉú±í.ѧºÅ GROUP BY ËùÔÚϵ
7£® ÉèÓÐÑ¡¿Î±í£¨Ñ§ºÅ£¬¿Î³ÌºÅ£¬³É¼¨£©£¬ÏÖÒª²éѯ¿¼ÊԳɼ¨×î¸ßµÄÈý¸öѧÉúµÄѧºÅ¡¢¿Î³ÌºÅºÍ³É¼¨£¬
°üÀ¨²¢ÁÐÇé¿ö¡£Ç벹ȫÏÂÁÐÓï¾ä£º TOP 3 WITH TIES, ORDER BY ³É¼¨ DESC SELECT _________ ѧºÅ£¬¿Î³ÌºÅ£¬³É¼¨ FROM Ñ¡¿Î±í _________ 8£® UNION²Ù×÷ÓÃÓںϲ¢¶à¸ö²éѯÓï¾äµÄ½á¹û£¬Èç¹ûÔںϲ¢½á¹ûʱ²»Ï£ÍûÈ¥µôÖظ´µÄÊý¾Ý£¬ÔòÔÚÓÃ
UNION²Ù×÷ʱӦʹÓÃ_________¹Ø¼ü×Ö¡£ ALL
9£® ½øÐÐ×ÔÁ¬½Ó²Ù×÷µÄÁ½¸ö±íÔÚÎïÀíÉÏΪһÕÅ±í¡£Í¨¹ý_________·½·¨¿É½«ÎïÀíÉϵÄÒ»ÕűíÔÚÂß¼
ÉϳÉΪÁ½ÕÅ±í¡£Æð±ðÃû
10£® FROM A LEFT JOIN B ON ¡Óï¾ä±íʾÔÚÁ¬½Ó½á¹ûÖв»ÏÞÖÆ_________±íÊý¾Ý±ØÐëÂú×ãÁ¬½Ó
10
¡¤11¡¤ Ìõ¼þ¡£ A
11£® ¶Ô·Ö×éºóµÄͳ¼Æ½á¹ûÔÙ½øÐÐɸѡʹÓõÄ×Ó¾äÊÇ_________¡£HAVING
12£® ÈôSELECTÓï¾äÖÐͬʱ°üº¬WHERE×Ó¾äºÍGROUP×Ӿ䣬ÔòÏÈÖ´ÐеÄÊÇ_________×Ӿ䡣
WHERE
Èý£® ¼ò´ðÌâ
1. ÔھۺϺ¯ÊýÖУ¬Äĸöº¯ÊýÔÚͳ¼Æʱ²»¿¼ÂÇNULL¡£ ´ð£ºCOUNT(*)
2. ÔÚLIKEÔËËã·ûÖС°%¡±µÄ×÷ÓÃÊÇʲô£¿ ´ð£ºÆ¥Åä0¸ö»ò¶à¸ö×Ö·û¡£
3. WHERE Age BETWEEN 20 AND 30×Ӿ䣬²éÕÒµÄAge·¶Î§ÊǶàÉÙ£¿ ´ð£ºAge´óÓÚµÈÓÚ20²¢ÇÒСÓÚµÈÓÚ30
4. WHERE Sdept NOT IN (¡®CS¡¯,¡¯IS¡¯,¡¯MA¡¯)£¬²éÕÒµÄÊý¾ÝÊÇʲô£¿ ´ð£º²éÕÒ¡®CS¡¯,¡¯IS¡¯,¡¯MA¡¯Èý¸öϵ֮ÍâµÄÆäËûϵ
5. ×ÔÁ¬½ÓÓëÆÕͨÄÚÁ¬½ÓµÄÖ÷ÒªÇø±ðÊÇʲô£¿
´ð£º×ÔÁ¬½ÓÖнøÐÐÁ¬½Ó²Ù×÷µÄ±íÔÚÎïÀíÉÏÊÇÒ»ÕÅ±í£¬¶øÆÕͨÄÚÁ¬½Ó½øÐÐÁ¬½ÓµÄ±íÔÚÎïÀíÉÏÊÇÁ½ÕÅ±í¡£
6. ÍâÁ¬½ÓÓëÄÚÁ¬½ÓµÄÖ÷ÒªÇø±ðÊÇʲô£¿
´ð£º½øÐÐÍâÁ¬½ÓµÄÁ½¸ö±íÖУ¬¿ÉÒÔÓÐÒ»ÕÅ±í²»Âú×ãÁ¬½ÓÌõ¼þ£¬¶ø½øÐÐÄÚÁ¬½ÓµÄÁ½¸ö±í±ØÐ붼Âú×ãÁ¬½ÓÌõ¼þ¡£
7. ÔÚʹÓÃUNIONºÏ²¢¶à¸ö²éѯÓï¾äµÄ½á¹ûʱ£¬¶Ô¸÷¸ö²éѯÓï¾äµÄÒªÇóÊÇʲô£¿ ´ð£º¸÷¸ö²éѯÓï¾äµÄÁиöÊý±ØÐëÏàͬ£¬¶ÔÓ¦ÁеÄÓïÒåÏàͬ£¬ÀàÐͼæÈÝ¡£
8. Ïà¹Ø×Ó²éѯÓëǶÌ××Ó²éѯÔÚÖ´Ðз½ÃæµÄÖ÷ÒªÇø±ðÊÇʲô£¿
´ð£ºÏà¹Ø×Ó²éѯµÄÖ´Ðйý³ÌÊÇÏÈÍâºóÄÚ£¬¶øǶÌ××Ó²éѯµÄÖ´Ðйý³ÌÊÇÏÈÄÚºóÍâ¡£¶øÇÒÏà¹Ø×Ó²éѯÖбØÐëÓÐÓëÍâ²ã²éѯµÄ¹ØÁª£¬¶øǶÌ××Ó²éѯÖУ¬ÄÚ¡¢Íâ²ã²éѯ֮¼äûÓйØÁª¹Øϵ¡£
9. Ö´ÐÐSELECT ¡ INOT ±íÃû FROM ¡Óï¾äʱ£¬¶Ô±íÃûµÄÒªÇóÊÇʲô£¿ ´ð£º±ØÐëÊÇÒ»¸ö²»´æÔÚµÄбíÃû¡£
10. ¶Ôͳ¼Æ½á¹ûµÄɸѡӦ¸ÃʹÓÃÄĸö×Ó¾äÍê³É£¿ ´ð£ºÊ¹ÓÃHAVING×Ó¾ä
11. ÔÚÅÅÐò×Ó¾äÖУ¬ÅÅÐòÒÀ¾ÝÁеÄÇ°ºó˳ÐòÊÇ·ñÖØÒª£¿ORDER BY C1,C2×Ó¾ä¶ÔÊý¾ÝµÄÅÅÐò˳ÐòÊÇ
ʲô£¿
´ð£ºÖØÒª£¬ÏµÍ³»á°´ÁеÄÏȺó˳Ðò½øÐÐÅÅÐò¡£
ÏÈ°´C1ÁнøÐÐÅÅÐò£¬ÔÚC1ÁÐÖµÏàͬʱÔÙ°´C2ÁнøÐÐÅÅÐò¡£
12. TOP ×Ó¾äµÄ×÷ÓÃÊÇʲô£¿
11
¡¤12¡¤ ´ð£ºÔÚ²éѯ½á¹û²úÉúºó£¬ÌáÈ¡½á¹ûµÄÇ°Èô¸ÉÐÐÊý¾Ý¡£
ËÄ£®ÉÏ»úÁ·Ï°
1£®²éѯѧÉúÑ¡¿Î±íÖеÄÈ«²¿Êý¾Ý¡£ ´ð£ºselect * from SC
2£®²éѯ¼ÆËã»úϵµÄѧÉúµÄÐÕÃû¡¢ÄêÁä¡£
´ð£ºselect sname,sage from student where sdept = '¼ÆËã»úϵ'
3. ²éѯ³É¼¨ÔÚ70¡«80·ÖÖ®¼äµÄѧÉúµÄѧºÅ¡¢¿Î³ÌºÅºÍ³É¼¨¡£
´ð£ºselect sno,cno,grade from sc on where grade between 70 and 80
4£® ²éѯ¼ÆËã»úϵÄêÁäÔÚ18¡«20Ö®¼äÇÒÐÔ±ðΪ¡°ÄС±µÄѧÉúµÄÐÕÃû¡¢ÄêÁä¡£ ´ð£ºselect sname,sage from student
where sdept = '¼ÆËã»úϵ' and sage between 18 and 20 and ssex = 'ÄÐ'
5£® ²éѯ¡°C001¡±ºÅ¿Î³ÌµÄ×î¸ß·Ö¡£
´ð£ºselect max(grade) from sc where cno = 'C001'
6. ²éѯ¼ÆËã»úϵѧÉúµÄ×î´óÄêÁäºÍ×îСÄêÁä¡£
´ð£ºselect max(sage) as max_age, min(sage) as min_age from student where sdept = '¼ÆËã»úϵ'
7. ͳ¼Æÿ¸öϵµÄѧÉúÈËÊý¡£
´ð£ºselect sdept,count(*) from student group by sdept
8. ͳ¼ÆÿÃſγ̵ÄÑ¡¿ÎÈËÊýºÍ¿¼ÊÔ×î¸ß·Ö¡£
´ð£ºselect cno, count(*),max(grade) from sc group by cno
9. ͳ¼Æÿ¸öѧÉúµÄÑ¡¿ÎÃÅÊýºÍ¿¼ÊÔ×ܳɼ¨£¬²¢°´Ñ¡¿ÎÃÅÊýÉýÐòÏÔʾ½á¹û¡£ ´ð£ºselect sno,count(*), sum(grade) from sc group by sno
order by count(*) asc
10. ²éѯ×ܳɼ¨³¬¹ý200·ÖµÄѧÉú£¬ÒªÇóÁгöѧºÅºÍ×ܳɼ¨¡£ ´ð£ºselect sno,sum(grade) from sc group by sno
having sum(grade) > 200
11. ²éѯѡ¿ÎÃÅÊý³¬¹ý2ÃŵÄѧÉúµÄѧºÅ¡¢Æ½¾ù³É¼¨ºÍÑ¡¿ÎÃÅÊý¡£
´ð£ºselect sno, avg(grade), count(*) from sc having count(*) > 2
12. ²éѯѡÁË¡°C002¡±¿Î³ÌµÄѧÉúµÄÐÕÃûºÍËùÔÚϵ¡£
´ð£ºselect sname,sdept from student s join sc on s.sno = sc.sno where cno = 'C002'
12