我想使用 50 页范围对页数进行排名。 我正在尝试根据页面范围显示我拥有的书籍 对页面计数进行排名。这意味着任何页数为 500-549 的书都具有相同的 秩;页数 550-599 具有相同的排名；页数 600-649 具有相同的排名； 页数 650-699 具有相同的排名等。我不能跳过排名数字。我该如何解决这个问题？
不确定这是否正确。这是我目前所拥有的:
set @rownum:= 0;
select page_count, Ranking
from(
SELECT case
when page_count between 0 and 49 then '0 - 49'
when page_count between 50 and 99 then '50 - 99'
when page_count between 100 and 149 then '100 - 149'
when page_count between 150 and 199 then '150 - 199'
when page_count between 200 and 249 then '200 - 249'
when page_count between 250 and 299 then '250 - 299'
when page_count between 300 and 349 then '300 - 349'
when page_count between 350 and 399 then '350 - 399'
when page_count between 400 and 449 then '400 - 449'
when page_count between 450 and 499 then '450 - 499'
when page_count between 500 and 549 then '500 - 549'
when page_count between 550 and 599 then '550 - 599'
when page_count between 600 and 649 then '600 - 649'
when page_count > 650 then 'Page Count over 650'
end as page_count
,
@rownum:= @rownum + 1 as Ranking
from a_bkinfo.books
)tbl
group by page_count;
为什么 50 -99 不合适？
这是表格:
create table a_bkinfo.books (
book_id integer not null
, title varchar(75) not null
, publ_id integer null
, year_publd integer not null
, isbn varchar(17) null
, page_count integer null
, list_price numeric(6,2) null
, constraint bk_books_pk primary key (book_id)
, constraint bk_books_publ_fk foreign key(publ_id)
references a_bkinfo.publishers (publ_id)
, constraint book_id_range check (book_id > 1000)
, constraint bk_page_count_ck check (page_count >= 0)
, constraint bk_price_ck check (list_price >= 0)
, constraint bk_books_year_ck check (year_publd >= 1850)
)engine = INNODB;
And here are the inserts:
-- books
insert into a_bkinfo.books values (1101, 'Programming SQL Server with VB.NET', 9000, 2002, '0735615357', 300, 59.99);
insert into a_bkinfo.books values (1102, 'Practical Standards for VB.NET', 9000, 2003, '0735613568', 250, 49.99);
insert into a_bkinfo.books values (1103, 'Selected Poems', 9456, 1949, null, 125, 12.00);
insert into a_bkinfo.books values (1104, 'Sibley Guide to Bird Life and Behavior', 9102, 2001, '0679451234', 604, 45.00);
insert into a_bkinfo.books values (1105, 'SQL:1999 Relational Language Concepts', 9745, 2002, '1558604561', 450, 59.95);
insert into a_bkinfo.books values (1106, 'SQL for Smarties', 9745, 1995, '1558603239', 250, 29.00);
insert into a_bkinfo.books values (1107, 'SQL Puzzles and Answers', 9745, 1997, '1558604537', 325, 25.00);
insert into a_bkinfo.books values (1108, 'Database Systems', 9325, 1996, null, 680, 39.95);
insert into a_bkinfo.books values (1109, 'Intro to DB Systems-7th Ed', 9325, 2000, '0201385902', 650, 80.00);
insert into a_bkinfo.books values (1110, 'Adv SQL:1999 Object_Relational Features', 9745, 2002, '1558606077', 520, 59.95);
insert into a_bkinfo.books values (1128, 'Temporal Data and the Relational Model', 9325, 2003, 'na', 275, 49.95);
insert into a_bkinfo.books values (1133, 'Leaves of Grass', 9623, 1902, null, 125, 19.95);
insert into a_bkinfo.books values (1142, 'Relational Database Theory', 9521, 1993, null, 879, 95.00);
insert into a_bkinfo.books values (1161, 'SQL Programming Style', 9745, 2005, '0120887975', 780, 35.00);
insert into a_bkinfo.books values (1162, 'Trees and Hierarchies', 9745, 2004, '1558609202', 350, 35.00);
insert into a_bkinfo.books values (1180, 'MySQL Database Design and Tuning', 9825, 2005, '9780672234650', 400, 49.99);
insert into a_bkinfo.books values (1175, 'MySQL in a Nutshell', 9822, 2008, '9780596514331', 538, 34.99);
insert into a_bkinfo.books values (1182, 'MySQL Cookbook', 9822, 2007, '9780596527082', 918, 49.99);
insert into a_bkinfo.books values (1185, 'MySQL Stored Procedures', 9822, 2007, '9780596100896', 595, 49.99);
insert into a_bkinfo.books values (1184, 'MySQL Developer''s Library', 9325, 2009, '9780672329388', 650, 49.99);
insert into a_bkinfo.books values (1301, 'ADO and Oracle Workbook', 9000, 2002, '0265615357', 0, 59.99);
insert into a_bkinfo.books values (1302, 'ADO: the ebook', 9000, 2002, '0852515358', null, 49.99);
insert into a_bkinfo.books values (1303, 'Rainbows and Rainbows', 9521, 2002, '0657895157', null, 59.99);
insert into a_bkinfo.books values (1304, 'Stories of Discoveries', 9325, 2002, '0777788887', 300, 59.99);
insert into a_bkinfo.books values (1305, 'Journeys Through Flatland', 9325, 1958, '0387515357', 100, 9.99);
insert into a_bkinfo.books values (1306, 'Myths of SQL', 9664, 2000, '0454615027', 2895,259.99);
insert into a_bkinfo.books values (1188, 'SQL for MySQL Developers', 9325, 2007, '9780314973851', 105, 49.99);
insert into a_bkinfo.books values (1199, 'SQL is Fun', null, 2007, null, 98, 19.99);
insert into a_bkinfo.books values (2001, 'Programming SQL Server 2005', 9822, 2006, '0596003216', 675, 49.99);
insert into a_bkinfo.books values (2002, 'SQL Server 2005 A Beginner''s Guide', 9030, 2006, '0072260939', 402, 39.99);
insert into a_bkinfo.books values (2003, 'SQL Server 2005 Developer''s Guide', 9030, 2006, '0072260998', 402, 49.99);
insert into a_bkinfo.books values (2004, 'SQL Server 2005 Stored Procedure Prg', 9030, 2006, '0072262888', 399, 59.99);
insert into a_bkinfo.books values (2005, 'Developer''s Guide to SQL Server 2005', 9325, 2006, '0321382188', 894, 59.99);
insert into a_bkinfo.books values (2006, 'T_SQL Programming (Inside series)', 9000, 2006, '9780756978', 390, 44.99);
insert into a_bkinfo.books values (2007, 'T_SQL Querying (Inside series)', 9000, 2006, '9780733132', 391, 44.99);
insert into a_bkinfo.books values (2008, 'SQL Server 2005 T_Sql Recipies', 9444, 2006, '159059570X', 503, 59.99);
insert into a_bkinfo.books values (2009, 'SQL Server 2005 Express Edition', 9664, 2006, '0764589237', 150, 29.99);
insert into a_bkinfo.books values (1258, '.Net Development for Microsoft Office', 9000, 2005, '0735621322', 500, 49.99);
insert into a_bkinfo.books values (1689, 'Programming Visual Basic 2005: The Language', 9000, 2006, '9780735621831', 980, 59.99);
insert into a_bkinfo.books values (1678, 'Pro .NET 2.0 Windows Forms and Controls VB 2005', 9444, 2006, '1590959693', 1002, 49.99);
insert into a_bkinfo.books values (1278, 'Beginning VB 2008 Databases', 9444, 2008, '9781590599471', 408, 44.99);
insert into a_bkinfo.books values (1478, 'Beginning OO Programming with VB 2005', 9444, 2006, '1590597695', 368, 44.99);
insert into a_bkinfo.books values (1894, 'Programming Visual Basic 2005', 9822, 2005, '0596009496', 548, 39.99);
insert into a_bkinfo.books values (1279, 'Data-Driven Services with Silverlight 2', 9822, 2009, '9780596523091', 336, 44.99);
insert into a_bkinfo.books values (1776, 'Doing Objects in Visual Basic 2005', 9325, 2007, '9780321320490', 500, 49.99);
insert into a_bkinfo.books values (1948, 'Framework Design Guidelines', 9325, 2006, '0321246756', 346, 44.99);
insert into a_bkinfo.books values (1077, 'Programming for Poets', 9456, 2009, null, 401, 40.25);
insert into a_bkinfo.books values (1835, 'Data Binding with Windows Forms 2.0', 9325, 2006, '032126892X', 634, 49.99);
insert into a_bkinfo.books values (1541, 'Freethinkers: A History of American Secularism', 9023, 2004, '9780805077766', 448, 12.79);
insert into a_bkinfo.books values (1542, 'The Great Agnostic: Robert Ingersoll and American Freethought',
9021, 2013, '9780300137255', 256, 16.99);
insert into a_bkinfo.books values (1543, 'Ties That Bind:The Story of an Afro-Cherokee Family in Slavery and Freedom',
9024, 2006, '9780520250024', 327, 26.96);
insert into a_bkinfo.books values (1544, 'The House on Diamond Hill: A Cherokee Plantation Story',
9024, 2012, '9780807872673', 336, 17.76);
insert into a_bkinfo.books values (1545, 'Team of Rivals: The Political Genius of Abraham Lincoln',
9776, 2006, '9780739469767', 944, 13.96);
insert into a_bkinfo.books values (1546, 'The Johnstown Flood', 9776, 1987, '9780671207144', 304, 10.39);
insert into a_bkinfo.books values (1677, 'Windows Forms 2.0 Programming', 9325, 2006, '0321267966', 982, 74.99);
insert into a_bkinfo.books values (1670, 'Applied .NET Framework Programming VB.NET', 9000, 2003, '0735678772', 608, 49.99);
insert into a_bkinfo.books values (1401, 'Visual Studio Tools for Office', 9325, 2006, '0321334884', 976, 54.99);
insert into a_bkinfo.books values (1537, 'The BedSide Book of Birds', 9725, 2005, '0385514832', 68, 29.95);
insert into a_bkinfo.books values (1357, 'Why Birds Sing', 9725, 2005, '046507135X', 240, 26.00);
insert into a_bkinfo.books values (1609, 'In the Company of Crows and Ravens', 9725, 2005, '0300100760', 376, 18.95);
insert into a_bkinfo.books values (1979, 'Pro VB 2008 and the .NET 3.5 Platform', 9444, 2008, '9781590598221',1368, 59.99);
insert into a_bkinfo.books values (1457, 'Visual Basic 2008 Recipes', 9444, 2008, '9781590599709', 300, 79.99);
insert into a_bkinfo.books values (1425, 'The Singing Life of Birds', 9561, 2005, '0618405682', 468, 28.09);
insert into a_bkinfo.books values (1978, 'Acoustic Communication in Birds Vol1', 9561, 1983, '9780124268012', 360,103.91);
insert into a_bkinfo.books values (1621, 'The Unfeathered Bird', 9020, 2013, '9780691151342', 304, 31.29);
insert into a_bkinfo.books values (1622, 'Bird Sense', 9020, 2012, '9780802779663', 265, 25.00);
insert into a_bkinfo.books values (1623, 'Lichens of North America', 9021, 2001, '9780300082494', 828,135.00);
insert into a_bkinfo.books values (1624, 'Outstanding Mosses and Liverworts of Pennsylvania and Nearby States',
9021, 2006, '9780976092575',9, 19.99);
insert into a_bkinfo.books values (1626, 'Bark: A Field Guide to Trees of the Northeast', 9021, 2011, '9781584658528', 280, 25.95);
insert into a_bkinfo.books values (1625, 'Winter Weed Finder: A Guide to Dry Plants in Winter (Nature Study Guides)',
9021, 1989, '9780912550176', 64, 4.95);
insert into a_bkinfo.books values (1627, 'The Ants', 9022, 1990, '9780674040755', 732,120.18);
insert into a_bkinfo.books values (1628, 'The Superorganism:The Beauty, Elegance, Strangeness of Insect Societies',
9902, 2008, '9780393067040', 544, 34.65);
insert into a_bkinfo.books values (1629, 'The Leafcutter Ants: Civilization by Instinct', 9022, 1990, '9780393338683', 160, 19.95);
insert into a_bkinfo.books values (1630, 'The Social Conquest of Earth', 9022, 2012, '9780871404138', 352, 27.95);
insert into a_bkinfo.books values (1448, 'Backyard Birdsong Guide: Western North America', 9561, 2008, '9780811863971',3192, 29.99);
insert into a_bkinfo.books values (1877, 'High Performance MySQL', 9822, 2008, '9780596101718', 708, 49.99);
insert into a_bkinfo.books values (1200, 'The Mismeasure of Man', 9902, 1996, '9780393314250', 488, 17.95);
insert into a_bkinfo.books values (1245, 'A Scientific Approach to SQL Testing', 9902, 2010, '9780366214250', 488, 52.95);
insert into a_bkinfo.books values (1774, 'Ever Since Darwin', 9902, 1992, '9780393308181', 288, 15.95);
insert into a_bkinfo.books values (1234, 'Hen''s Teeth and Horse''s Toes ', 9902, 1994, '9780393311037', 416, 17.95);
insert into a_bkinfo.books values (1269, 'Querying XML', 9745, 2006, '9781558607118', 848, 63.95);
insert into a_bkinfo.books values (1525, 'Interface-Oriented Design', 9725, 2006, '0976697050', 213, 29.99);
insert into a_bkinfo.books values (1619, 'The Oject-Oriented Thought Process', 9725, 2004, '9780672326110', 158, 29.99);
insert into a_bkinfo.books values (1483, 'Programming with XML', 9745, 2008, null, 125, 19.99);
insert into a_bkinfo.books values (2017, 'Functional Programming', 9528, 2010, '9781933988924', 528, 49.99);
insert into a_bkinfo.books values (2018, 'Oracle Database 11g SQL', 9030, 2008, '9780071498500', 650, 49.99);
insert into a_bkinfo.books values (2025, 'Oracle SQL Fundamentals I Exam Guide', 9030, 2008, '9780071597869', 572, 59.99);
insert into a_bkinfo.books values (2027, 'Mastering Oracle SQL and SQL-Plus', 9444, 2005, '9781590594487', 464, 39.99);
insert into a_bkinfo.books values (2028, 'Mastering Oracle Databases', 9444, 2010, '9781599594487', 464, 59.99);
insert into a_bkinfo.books values (2029, 'The Forgotten Bird Strikes Back ', 9030, 2010, '9091599594487', 5, 1.99);
insert into a_bkinfo.books values (2031, 'Comparative SQL', 9444, 2013, '9781599591237', 750, 99.99);
insert into a_bkinfo.books values (2032, 'Oracle and the rest of the world', 9030, 2013, '9091599593217', 250, 55.99);
insert into a_bkinfo.books values (2622, 'Outstanding Bryophytes', 9021, 2013, null,956, 89.99);
insert into a_bkinfo.books values (2623, 'Hornworts and Liverworts in your Garden ', 9021, 2013, null,501, 29.99);
最佳答案
NULL需要处理。所以请使用IS NULL。要为您的自定义范围创建订单，您必须使用 一个技巧。排序现在发生在 Character wise.. not number wise.. 所以 50在450之后..
简单的方法是让它固定格式..就像附加一个'0'..从'50'->'050'..你就完成了。 也用 LPAD '0' 将其设为 3 位数。我已经为您修改了查询。 !
SET @rownum:= 0;
SELECT page_count, Ranking
from(
SELECT CASE
WHEN page_count BETWEEN 0 AND 49 OR page_count IS NULL THEN '000 - 049'
WHEN page_count BETWEEN 50 AND 99 THEN '050 - 099'
WHEN page_count BETWEEN 100 AND 149 THEN '100 - 149'
WHEN page_count BETWEEN 150 AND 199 THEN '150 - 199'
WHEN page_count BETWEEN 200 AND 249 THEN '200 - 249'
WHEN page_count BETWEEN 250 AND 299 THEN '250 - 299'
WHEN page_count BETWEEN 300 AND 349 THEN '300 - 349'
WHEN page_count BETWEEN 350 AND 399 THEN '350 - 399'
WHEN page_count BETWEEN 400 AND 449 THEN '400 - 449'
WHEN page_count BETWEEN 450 AND 499 THEN '450 - 499'
WHEN page_count BETWEEN 500 AND 549 THEN '500 - 549'
WHEN page_count BETWEEN 550 AND 599 THEN '550 - 599'
WHEN page_count BETWEEN 600 AND 649 THEN '600 - 649'
WHEN page_count >=650 THEN 'Page Count over 650'
END AS page_count
,
@rownum:= @rownum + 1 AS Ranking
FROM books
)tbl
GROUP BY page_count;
关于mysql - 有人可以帮我按别名分组和处理空值吗？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20580109/