{"id":525,"date":"2014-09-16T10:59:50","date_gmt":"2014-09-16T02:59:50","guid":{"rendered":"http:\/\/www.royalwzy.com\/?p=525"},"modified":"2015-09-10T21:53:02","modified_gmt":"2015-09-10T13:53:02","slug":"lag%e5%92%8clead","status":"publish","type":"post","link":"http:\/\/www.royalwzy.com\/?p=525","title":{"rendered":"lag()\u548clead()"},"content":{"rendered":"

LAG()\u548cLEAD()\u7edf\u8ba1\u51fd\u6570\u53ef\u4ee5\u5728\u4e00\u6b21\u67e5\u8be2\u4e2d\u53d6\u51fa\u540c\u4e00\u5b57\u6bb5\u7684\u524dN\u884c\u7684\u6570\u636e\u548c\u540eN\u884c\u7684\u503c\u3002\u8fd9\u79cd\u64cd\u4f5c\u53ef\u4ee5\u4f7f\u7528\u5bf9\u76f8\u540c\u8868\u7684\u8868\u8fde\u63a5\u6765\u5b9e\u73b0\uff0c\u4e0d\u8fc7\u4f7f\u7528LAG\u548c LEAD\u6709\u66f4\u9ad8\u7684\u6548\u7387\u3002\u4ee5\u4e0b\u6574\u7406\u7684LAG()\u548cLEAD()\u4f8b\u5b50\uff1a<\/p>\n

LAG(EXPRESSION,<OFFSET>,<DEFAULT>)
\nSQL> select year,region,profit ,lag (profit,1) over (order by year)\u00a0 as 51xit_exp from test;
\nYEAR REGION\u00a0\u00a0\u00a0\u00a0\u00a0 PROFIT 51xit_exp
\n—- ——- ———- ————-
\n2003 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88
\n2003 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88
\n2003 Central\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88
\n2003 Central\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101
\n2003 East\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100
\n2004 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 77\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102
\n2004 East\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 103\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 77
\n2004 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 89\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 103<\/p>\n

LEAD(EXPRESION,<OFFSET>,<DEFAULT>)
\nSQL> select year,region,profit ,lead (profit,1) over (order by year)\u00a0 as next_year_exp from test;
\nYEAR REGION\u00a0\u00a0\u00a0\u00a0\u00a0 PROFIT NEXT_YEAR_EXP
\n—- ——- ———- ————-
\n2003 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88
\n2003 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101
\n2003 Central\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100
\n2003 Central\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102
\n2003 East\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 77
\n2004 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 77\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 103
\n2004 East\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 103\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 89
\n2004 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 89<\/p>\n

Lag\u51fd\u6570\u4e3aLag(exp,N,defval)\uff0cdefval\u662f\u5f53\u8be5\u51fd\u6570\u65e0\u503c\u53ef\u7528\u7684\u60c5\u51b5\u4e0b\u8fd4\u56de\u7684\u503c\u3002Lead\u51fd\u6570\u7684\u7528\u6cd5\u7c7b\u4f3c\u3002
\nLead\u548cLag\u51fd\u6570\u4e5f\u53ef\u4ee5\u4f7f\u7528\u5206\u7ec4\uff0c\u4ee5\u4e0b\u662f\u4f7f\u7528region\u5206\u7ec4\u7684\u4f8b\u5b50\uff1a
\nSQL> select year,region,profit , lag (profit,1,0) over (PARTITION BY region order by year)\u00a0\u00a0\u00a0 as 51xit_exp from test;
\nYEAR REGION\u00a0\u00a0\u00a0\u00a0\u00a0 PROFIT 51xit_exp
\n—- ——- ———- ————-
\n2003 Central\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0
\n2003 Central\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 100\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 101
\n2003 East\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0
\n2004 East\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 103\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 102
\n2003 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 0
\n2003 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88
\n2004 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 77\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 88
\n2004 West\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 89\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 77<\/p>\n

\u4e00SQL\u95ee\u9898\u89e3\u7b54\uff1a
\n\u95ee\u9898\uff1a
\nCREATE\u00a0\u00a0 TABLE\u00a0 ldy_temp_2
\n(
\n\u5206\u5c40\u00a0\u00a0\u00a0 VARCHAR(255),
\n\u6d3e\u51fa\u6240\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u8bc1\u4ef6\u7c7b\u578b\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u8bc1\u4ef6\u53f7\u7801\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u59d3\u540d\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u6027\u522b\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u884c\u653f\u533a\u5212\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u65c5\u9986\u540d\u79f0\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u65c5\u9986\u5730\u5740\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u623f\u95f4\u53f7\u00a0\u00a0\u00a0 VARCHAR(255) ,
\n\u5165\u4f4f\u65f6\u95f4\u00a0\u00a0\u00a0 VARCHAR(255) ,
\ncol012\u00a0\u00a0\u00a0 VARCHAR(255)
\n);<\/p>\n

INSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1234′,’ZHANGTAO’,’A’,’20100506′);
\nINSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1234′,’ZHANGTAO’,’A’,’20100507′);
\nINSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1234′,’ZHANGTAO’,’B’,’20100508′)\uff1b<\/p>\n

INSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1234′,’ZHANGTAO’,’A’,’20100509′);
\nINSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1235′,’ZZZZ’,’A’,’20100506′);
\nINSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1235′,’ZZZZ’,’B’,’20100507′);
\nINSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1235′,’ZZZZ’,’A’,’20100508′);
\nINSERT INTO LDY_TEMP_2
\n(\u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4)
\nVALUES(‘1235′,’ZZZZ’,’B’,’20100509′);<\/p>\n

\u5efa\u8868\u8bed\u53e5\u548c\u6d4b\u8bd5\u6570\u636e\u5df2\u7ecf\u7ed9\u51fa\u00a0 \u8bf7\u95ee\u00a0 \u5982\u4f55\u67e5\u627e\u76f8\u90bb\u4e24\u6b21\u5165\u4f4f\u65c5\u9986\u540d\u79f0\u4e0d\u540c\u7684\u4eba\uff1b\u4e5f\u5c31\u662f\u8bf4 \u4e00\u4e2a\u4eba\u7684\u8bc1\u4ef6\u53f7\u7801\u662f123\u7684\u8bdd \u90a3\u4e48\u8fd9\u4e2a\u4eba\u7684\u4fe1\u606f\u6309\u7167\u5165\u4f4f\u65f6\u95f4\u6392\u5e8f\u540e\u00a0 \u76f8\u90bb\u4e24\u6761\u6570\u636e\u7684\u65c5\u9986\u540d\u79f0\u4e0d\u80fd\u4e00\u6837 \u3002<\/p>\n

\u89e3\u7b54\uff1a
\nwith temp_a as
\n(select
\nt.\u8bc1\u4ef6\u53f7\u7801,
\nt.\u65c5\u9986\u540d\u79f0,
\nt.\u5165\u4f4f\u65f6\u95f4,
\nlag(t.\u65c5\u9986\u540d\u79f0) over (partition by t.\u8bc1\u4ef6\u53f7\u7801 order by t.\u5165\u4f4f\u65f6\u95f4) as lagname
\nfrom ldy_temp_2 t)
\nselect \u8bc1\u4ef6\u53f7\u7801,\u59d3\u540d,\u65c5\u9986\u540d\u79f0,\u5165\u4f4f\u65f6\u95f4
\nfrom ldy_temp_2 a
\nwhere a.\u8bc1\u4ef6\u53f7\u7801 not in (select b.\u8bc1\u4ef6\u53f7\u7801 from temp_a b where\u00a0 b.\u65c5\u9986\u540d\u79f0=b.lagname)<\/p>\n","protected":false},"excerpt":{"rendered":"

LAG()\u548cLEAD()\u7edf\u8ba1\u51fd\u6570\u53ef\u4ee5\u5728\u4e00\u6b21\u67e5\u8be2\u4e2d\u53d6\u51fa\u540c\u4e00\u5b57\u6bb5\u7684\u524dN\u884c\u7684\u6570\u636e\u548c\u540eN\u884c\u7684\u503c\u3002\u8fd9\u79cd\u64cd\u4f5c\u53ef\u4ee5\u4f7f\u7528\u5bf9\u76f8\u540c […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[34,2],"class_list":["post-525","post","type-post","status-publish","format-standard","hentry","category-oracle","tag-oracle","tag-oracle_basics"],"_links":{"self":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts\/525","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=525"}],"version-history":[{"count":1,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts\/525\/revisions"}],"predecessor-version":[{"id":1011,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=\/wp\/v2\/posts\/525\/revisions\/1011"}],"wp:attachment":[{"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=525"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=525"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.royalwzy.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=525"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}