DML<\/p>\n\n\n\n
\u65b0\u589e\u8cc7\u6599<\/strong> \u65b0\u589e\u5f9esql\u6488\u51fa\u4f86\u7684\u8cc7\u6599 …………….<\/p>\n\n\n\n \u66f4\u65b0\u8cc7\u6599 value\u53ef\u4ee5\u70ba<\/strong> …………….<\/p>\n\n\n\n \u522a\u9664\u8cc7\u6599 \u6e05\u7a7a\u8cc7\u6599\u8868<\/strong> ps: …………….<\/p>\n\n\n\n \u67e5\u8a62\u8cc7\u6599 \u5e38\u7528\u7684express\u6709<\/strong> WHERE condition\u5e38\u898b\u7528\u6cd5<\/strong> ………………………………………………………………………………………..<\/p>\n\n\n\n \u805a\u5408\u51fd\u6578<\/strong><\/p>\n\n\n\n \u805a\u5408\u51fd\u6578\u57fa\u672c\u7528\u6cd5<\/strong> \u4f9dgroup\u5206\u7d44\u805a\u5408\u51fd\u6578\u7d50\u679c<\/strong> ex1: \u904e\u6ffegroup\u7684\u7d50\u679c<\/strong> ex1: ROLLUP<\/strong> ex: CUBE ex: ………………………………………………………………………………………..<\/p>\n\n\n\n \u4f7f\u7528WHERE\u8a9e\u6cd5\u5408\u4f75<\/strong> ex1: \u4ee5\u4e0b\u70ba\u591a\u8cc7\u6599\u8868\u5408\u4f75,\u4ee5inner join\u70ba\u4f8b ex1: ex1: ………………….. <\/p>\n\n\n\n union<\/strong> union all<\/strong> ex: ex: ex: DML \u65b0\u589e\u8cc7\u6599\u65b0\u589e1\u7b46\u8cc7\u6599INSERT INTO < …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"fifu_image_url":"","fifu_image_alt":"","_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[16],"tags":[],"class_list":["post-581","post","type-post","status-publish","format-standard","hentry","category-database"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/581","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/comments?post=581"}],"version-history":[{"count":0,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/posts\/581\/revisions"}],"wp:attachment":[{"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/media?parent=581"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/categories?post=581"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/systw.net\/note\/wp-json\/wp\/v2\/tags?post=581"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\u65b0\u589e1\u7b46\u8cc7\u6599
INSERT INTO < tablename>(column-list) value (value-list)<\/strong>
\u65b0\u589e\u591a\u7b46\u8cc7\u6599
INSERT INTO < tablename>(column-list) value
(value-list 1),(value-list 2),…..(value-list n);<\/strong><\/p>\n\n\n\n
INSERT INTO < tablename>(column-list) sub-sql<\/strong>
ex:
INSERT INTO company (company_id,contact,telnet, address)
SELECT id, contact,telnet,address FROM customer WHERE company=systw<\/p>\n\n\n\n
UPDATE < tablename> SET < column1=value1>[,< column2=value2>,…] [WHERE < condition>]<\/strong>
ex:
UPDATE \u7522\u54c1\u8cc7\u6599 SET \u5eab\u5b58\u91cf = 300, \u5b89\u5168\u5b58\u91cf = 50 WHERE \u7522\u54c1\u7de8\u865f = 13
UPDATE employee SET salary = salary*1.1
UPDATE employee SET salary = salary+(select avg(salary) from employee)*0.1<\/p>\n\n\n\n
\u6307\u5b9a\u7684\u8cc7\u6599
default \u4fdd\u7559\u5b57,\u4f7f\u7528\u8a72\u5c6c\u6027\u7684\u9810\u8a2d\u503c<\/p>\n\n\n\n
DELETE FROM < tablename> WHERE < condition><\/strong><\/p>\n\n\n\n
\u6709\u4ee5\u4e0b2\u7a2e\u65b9\u6cd5
TRUNCATE TABLE < tablename><\/strong>
\u3000\u4e26\u4e0d\u6703\u5c07\u6240\u522a\u9664\u7684\u57f7\u884c\u904e\u7a0b\u8a18\u9304\u65bclog file(\u4ea4\u6613\u65e5\u8a8c\u6a94)\u4e2d
DELETE FROM < tablename><\/strong>
\u3000\u6703\u5c07\u6240\u6709\u88ab\u522a\u9664\u7684\u8cc7\u6599\u5168\u90e8\u8a18\u9304\u65bclog file\u4e2d,\u4e5f\u6703\u986f\u793a\u522a\u9664\u7684\u6578\u91cf
ps:
\u5728\u522a\u9664\u5927\u91cf\u8cc7\u6599\u6642\uff0cTRUNCATE\u8f03\u6709\u6548\u7387<\/p>\n\n\n\n
sql server\u8a2d\u5b9alog
1\u8cc7\u6599\u5eab>\u6307\u5b9a\u7684\u8cc7\u6599\u5eab>\u5167\u5bb9
2\u9078\u9805>\u5fa9\u539f,\u6a21\u578b:[\u7c21\u6613|\u5b8c\u6574|\u5927\u91cf\u767b\u5165]
ps:log\u8981\u4f7f\u7528\u53e6\u4e00\u5957\u5de5\u5177\u624d\u6709\u8fa6\u6cd5\u5206\u6790<\/p>\n\n\n\n
SELECT < express> FROM < tablename>
[WHERE < condition>]
[GROUP BY < column-list>]
[HAVING < condition>]
[ORDER BY < column1> [ASC|DESC] [,< column2> [ASC|DESC],…]]<\/strong><\/p>\n\n\n\n
< column-list | *><\/strong> \u6307\u5b9a\u8981\u986f\u793a\u7684\u6b04\u4f4d\u6216\u986f\u793a\u6240\u6709\u6b04\u4f4d
DISTINCT < column><\/strong> \u6307\u5b9a\u8a72\u6b04\u4f4d\u7684\u91cd\u8907\u503c\u53ea\u8f38\u51fa\u4e00\u7b46\u5373\u53ef
< column> AS < newname><\/strong> \u8a2d\u5b9a\u6b04\u4f4d\u5225\u540d,\u53ef\u6539\u8b8a\u8f38\u51fa\u6642\u6b04\u4f4d\u7684\u540d\u7a31
< operation> AS < newname><\/strong> \u5c07\u6b04\u4f4d\u505a\u904b\u7b97\u4e26\u7d66\u4e88\u5225\u540d
< sub-sql><\/strong> \u6b04\u4f4d\u7684\u503c\u4f7f\u7528sub-sql\u5217\u51fa
ex:SELECT \u5be6\u969b\u55ae\u50f9*\u6578\u91cf AS \u5c0f\u8a08 FROM \u8a02\u55ae\u660e\u7d30
ex:SELECT fname+’ \u2018+lname AS name FROM employee<\/p>\n\n\n\n
%<\/strong> \u8868\u793a\u4efb\u610f\u9577\u5ea6
ex:\u627e\u51faid\u70ba3\u958b\u982d\u7684\u503c id like ‘3%’
_ or ?<\/strong> \u8868\u793a1\u500b\u5b57\u5143
ex:\u627e\u51faid\u768410\u4f4d\u6578\u70ba2,\u4e14\u53ea\u67093\u500b\u4f4d\u6578\u7684\u503c id like ‘_2_’
[NOT] IN (< value1,value2[,value3,…] | sub-sql>)<\/strong> \u8868\u793a\u591a\u500bor
ex:
sid=1 or sid=6 or sid=10\u7b49\u540c\u65bcsid IN (1, 6, 10)
sid IN (select sid from employee)
[NOT] BETWEEN < min> AND < max><\/strong> \u8868\u793a\u5728min\u548cmax\u7bc4\u570d\u4e4b\u9593
ex:sid BETWEEN 5 AND 10 \u7b49\u540c\u65bc sid >5 and sid < 10
[NOT] EXIST (< sub-sql>)<\/strong> \u6e2c\u8a66\u662f\u5426\u5b58\u5728,\u6216\u6e2c\u8a66\u662f\u5426\u4e0d\u5b58\u5728
ex:
SELECT \u54e1\u5de5\u7de8\u865f, \u59d3\u540d FROM \u54e1\u5de5 WHERE EXISTS
( SELECT * FROM \u8a02\u55ae WHERE \u54e1\u5de5\u7de8\u865f = \u54e1\u5de5.\u54e1\u5de5\u7de8\u865f)<\/p>\n\n\n\n
ps:
SELECT id, company FROM customer
WHERE company IN ( SELECT supply FROM supply)
ORDER BY id
\u7b49\u540c\u65bc
SELECT id, company FROM customer, supply
WHERE company = supply
ORDER BY id<\/p>\n\n\n\n
\u683c\u5f0f\u70ba
SELECT < aggregate function> FROM < tablename><\/strong>
ex:
\u5217\u51fa\u6240\u6709employee\u7684\u7e3d\u7b46\u6578
SELECT COUNT(id) AS allemployee FROM employee<\/p>\n\n\n\n
\u683c\u5f0f\u70ba
SELECT < aggregate function> FROM < tablename>
GROUP BY < column1 [,column2,…]><\/strong>
\u6210\u529f\u5206\u7d44\u9700\u7b26\u5408\u4ee5\u4e0b\u5176\u4e2d\u4e00\u500b\u689d\u4ef6
\u689d\u4ef61,\u88ab\u805a\u5408\u51fd\u6578\u6240\u5305\u542b
\u689d\u4ef62,\u5206\u7fa4\u7684\u689d\u4ef6
ex:
\u5217\u51fa\u7537\u5973employee\u5404\u5225\u7684\u7e3d\u7b46\u6578
SELECT sex,COUNT(id) FROM employee GROUP BY sex
\u5217\u51fa\u6bcf\u500b\u90e8\u9580\u7684\u7537\u5973\u54e1\u5de5\u5404\u5225\u7684\u6578\u91cf
SELECT dno,sex,COUNT(id) FROM employee GROUP BY dno,sex<\/p>\n\n\n\n
\u5217\u51fa\u6bcf\u500b\u54e1\u5de5\u7e3d\u5de5\u6642<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
works_on(essn,pro,hours)
\u8a9e\u6cd5\u5982\u4e0b
\u7b26\u5408\u689d\u4ef62,group by\u7684\u6b04\u4f4d\u548cselect\u6b04\u4f4d\u76f8\u540c
SELECT ssn,fname,lname,sum(hours) FROM employee,works_on
WHERE essn=ssn GROUP BY ssn,fname,lname
\u7b26\u5408\u689d\u4ef61,fname\u4f7f\u7528\u805a\u5408\u51fd\u6578max,lname\u4f7f\u7528\u805a\u5408\u51fd\u6578min
SELECT ssn,max(fname),min(lname),sum(hours) FROM employee,works_on
WHERE essn=ssn GROUP BY ssn
ex2
\u5217\u51fa\u6bcf\u500b\u54e1\u5de5\u7e3d\u5de5\u6642\u7684\u767e\u5206\u6bd4<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
works_on(essn,pro,hours)
\u8a9e\u6cd5\u5982\u4e0b
SELECT ssn,fname,lname,sum(hours)\/(select sum(hours) from works_on)*100
FROM employee,works_on
WHERE essn=ssn GROUP BY ssn,fname,lname<\/p>\n\n\n\n
\u683c\u5f0f\u70ba
SELECT < aggregate function> FROM < tablename>
GROUP BY < column1 [,column2,…]>
HAVING < aggregate column condition><\/strong><\/p>\n\n\n\n
\u5217\u51fa\u6bcf\u500b\u54e1\u5de5\u7e3d\u5de5\u6642\u5927\u65bc100\u7684\u54e1\u5de5<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
works_on(essn,pro,hours)
\u8a9e\u6cd5\u5982\u4e0b
SELECT ssn,fname,lname,sum(hours) FROM employee,works_on
WHERE essn=ssn GROUP BY ssn,fname,lname
HAVING sum(hours)>100<\/p>\n\n\n\n
\u53ef\u7528\u4f86\u5404\u5225\u7e3d\u8a08
\u683c\u5f0f\u70ba
GROUP BY < column1 [,column2,…]> with rollup<\/strong>
ps:
mysql\u4e0d\u652f\u63f4order by,\u82e5\u8981\u6392\u5e8f\u5247\u8981\u76f4\u63a5\u5728\u6b04\u4f4d\u5f8c\u63a5asc\u6216desc <\/strong><\/p>\n\n\n\n
\u5047\u8a2dSQL\u8a9e\u6cd5\u7d50\u679c\u5982\u4e0b
SELECT year, SUM(profit) FROM sales GROUP BY year
2000 , 4525
2001 , 3010
\u4f7f\u7528ROLLUP\u53ef\u505a\u7e3d\u8a08
SELECT year, SUM(profit) FROM sales GROUP BY year WITH ROLLUP;
2000 , 4525
2001 , 3010
NULL , 7535<\/strong>
ex:
\u7531\u5927\u5230\u5c0f\u6392\u5e8f
SELECT year, SUM(profit) FROM sales GROUP BY year desc WITH ROLLUP;
2001 , 3010
2000 , 4525
NULL , 7535<\/p>\n\n\n\n
<\/strong>\u53ef\u7528\u4f86\u5c0d\u6307\u5b9a\u6b04\u4f4d\u505a\u6240\u6709\u7d44\u5408\u7684\u7e3d\u8a08
\u683c\u5f0f\u70ba
GROUP BY < column1 [,column2,…]> with cube<\/strong><\/p>\n\n\n\n
\u5047\u8a2dsql\u8a9e\u6cd5\u5982\u4e0b
SELECT ip,desturl,count FROM ip2url GROUP BY ip,desturl
\u57f7\u884c\u7d50\u679c\u70ba
ip,desturl,count
10.1.1.1,tw.yahoo.com,12
10.1.1.1,www.pchome.com,5
10.1.1.2,tw.yahoo.com,18
10.1.1.3,www.google.com,4
1
\u82e5\u4ee5rollup\u70ba\u4f8b
SELECT ip,desturl,count FROM ip2url GROUP BY ip,desturl WITH rollup;
\u57f7\u884c\u7d50\u679c\u70ba
ip,desturl,count
10.1.1.1,tw.yahoo.com,12
10.1.1.1,www.pchome.com,5
10.1.1.1,null,17<\/strong>
10.1.1.2,tw.yahoo.com,18
10.1.1.2,null,18<\/strong>
10.1.1.3,www.google.com,4
10.1.1.3,null,4<\/strong>
null,null,39<\/strong>
2
\u82e5\u4ee5cube\u70ba\u4f8b
SELECT ip,desturl,count FROM ip2url GROUP BY ip,desturl WITH cube;
\u57f7\u884c\u7d50\u679c\u70ba
ip,desturl,count
10.1.1.1,tw.yahoo.com,12
10.1.1.1,www.pchome.com,5
10.1.1.1,null,17<\/strong>
10.1.1.2,tw.yahoo.com,18
10.1.1.2,null,18<\/strong>
10.1.1.3,www.google.com,4
10.1.1.3,null,4<\/strong>
null,null,39<\/strong>
null,tw.yahoo.com,30
null,www.pchome.com,5
null,www.google.com,4<\/strong><\/p>\n\n\n\n
\u5408\u4f75\u8cc7\u6599\u8868<\/strong><\/p>\n\n\n\n
\u5c6c\u65bcsql89\u683c\u5f0f
\u7b49\u540c\u65bcinner join ,\u4e5f\u5c31\u662f (A)|X|a=b(B)
2\u500b\u8cc7\u6599\u8868\u7684\u5408\u4f75\u67e5\u8a62\u683c\u5f0f\u5982\u4e0b
SELECT * FROM < table1,table2>
WHERE < table1.column = table2.column><\/strong>
3\u500b\u8cc7\u6599\u8868\u7684\u5408\u4f75\u67e5\u8a62
SELECT * FROM < table1,table2,table3>
WHERE < table1.column = table2.column &&
table2.column = table3.column><\/strong>
4\u500b\u8cc7\u6599\u8868\u7684\u5408\u4f75\u67e5\u8a62
SELECT * FROM < table1,table2,table3,table4>
WHERE < table1.column = table2.column &&
table2.column = table3.column &&
table3.column = table4.column><\/strong><\/p>\n\n\n\n
\u5217\u51fa\u90e8\u9580\u4e3b\u7ba1\u540d\u7a31(fname,lname)<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
department(dname,dnumber,mgr_ssn,mgr_start_date)
\u8a9e\u6cd5\u5982\u4e0b
\u4f7f\u7528where\u65b9\u6cd5<\/strong>,step1 n*m=x \u5148\u5408\u4f75, step2\u5728\u904e\u6ffe\u5408\u4f75\u7d50\u679cx
SELECT fname,lname FROM employee,department WHERE ssn=mgr_ssn
\u4f7f\u7528in\u65b9\u6cd5<\/strong>,step1 \u5148\u904e\u6ffem=y ,step2\u5728\u5f9en\u6311\u51fa\u7b26\u5408y\u7684(\u6548\u80fd\u8f03\u5dee)
SELECT fname,lname FROM employee WHERE ssn IN (SELECT mgr_ssn FROM department)
\u4f7f\u7528sub-sql\u65b9\u6cd5(\u6548\u80fd\u8f03\u597d)<\/strong>
SELECT fname,lname FROM employee,(SELECT mgr_ssn FROM department) AS mgr WHERE ssn=mgr_ssn
ex2:
\u5217\u51faproductx\u6240\u53c3\u8207\u7684\u54e1\u5de5\u59d3\u540d\u8207\u5de5\u6642(fname,lname,hours)<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
project(pname,pnumber,plocation,dnum)
works_on(essn,pro,hours)
\u8a9e\u6cd5\u5982\u4e0b
\u4f7f\u7528where\u65b9\u6cd5<\/strong>
SELECT fname,lname,hours FROM employee,project,works_on
WHERE pnumber=pno && ssn=essn && pname=’productx’
\u4f7f\u7528in\u65b9\u6cd5<\/strong>
SELECT fname,lname,hours FROM employee,works_on
WHERE essn=ssn && pno IN (SELECT pnumber FROM project WHERE pname=’productx’)
\u4f7f\u7528sub-sql\u65b9\u6cd5<\/strong>
SELECT fname,lname,hours
FROM employee,works_on,(SELECT pnumber FROM project WHERE pname=’productx’) AS p
WHERE essn=ssn && pno =pnumber<\/p>\n\n\n\n
\u4f7f\u7528JOIN\u8a9e\u6cd5\u5408\u4f75<\/strong>
\u5c6c\u65bcsql92\u683c\u5f0f
\u683c\u5f0f\u70ba
SELECT * FROM ( < table1> < join type> < table2> ON < table1.column = table2.column> )<\/strong>
join type\u53ef\u9078inner join,left outer join,right outer join<\/p>\n\n\n\n
2\u500b\u8cc7\u6599\u8868\u7684\u5408\u4f75\u67e5\u8a62
SELECT * FROM ( < table1> INNER JOIN < table2> ON < table1.column = table2.column> )<\/strong>
3\u500b\u8cc7\u6599\u8868\u7684\u5408\u4f75\u67e5\u8a62
SELECT * FROM ( (< table1> INNER JOIN < table2> ON < table1.column = table2.column>)
INNER JOIN < table3> ON < table2.column = table3.column> )<\/strong>
4\u500b\u8cc7\u6599\u8868\u7684\u5408\u4f75\u67e5\u8a62
SELECT * FROM ( < table1> INNER JOIN < table2> ON < table1.column = table2.column>
INNER JOIN < table3> ON < table2.column = table3.column>
INNER JOIN < table4> ON < table3.column = table4.column> )<\/strong><\/p>\n\n\n\n
\u5217\u51fa\u6bcf\u500b\u90e8\u9580\u7684\u7d93\u7406\u59d3\u540d (DEPARTMENT.dname,EMPLOYEE.fname,EMPLOYEE.lname)<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
department(dname,dnumber,mgr_ssn,mgr_start_date)
\u8a9e\u6cd5\u5982\u4e0b
SELECT dname,fname,lname FROM department INNER JOIN employee ON mgr_ssn=ssn
ex2:
\u5217\u51fa\u6bcf\u500b\u54e1\u5de5\u53c3\u8207\u5c08\u6848\u7684\u5de5\u6642\u8868(fname,lname,pname,hours)<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
project(pname,pnumber,plocation,dnum)
works_on(essn,pro,hours)
\u8a9e\u6cd5\u5982\u4e0b
\u4f7f\u7528innerjoin\u65b9\u6cd5<\/strong>
SELECT fname,dname,pname,hours FROM (employee INNER JOIN works_on ON ssn=essn) INNER JOIN project ON pnumber=pno
\u4f7f\u7528where\u65b9\u6cd5<\/strong>
SELECT fname,dname,pname,hours FROM employee,works_on,project
WHERE employee.ssn=works_on.essn && works_on.pno=project.pnumber
ex3:
\u5217\u51fa\u6240\u6709\u54e1\u5de5\u8207\u54e1\u5de5\u89aa\u5c6c\u59d3\u540d(fname,lname,dependent_name)<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
dependent(essn,depandent_name,sex,bdate,relationship)
\u8a9e\u6cd5\u5982\u4e0b
\u4f7f\u7528left outer join\u65b9\u6cd5<\/strong>
SELECT fname,lname,dependent_name FROM employee LEFT OUTER JOIN dependent ON ssn=essn
\u4f7f\u7528right outer join\u65b9\u6cd5<\/strong>
SELECT fname,lname,dependent_name FROM dependent RIGHT OUTER JOIN employee ON ssn=essn
\u4ee5ssn\u70ba\u4e3b,\u4f7f\u7528where\u65b9\u6cd5<\/strong>
SELECT fname,lname,dependent_name FROM dependent,employee WHERE essn=*ssn
\u7b49\u540c\u65bc
SELECT fname,lname,dependent_name FROM dependent,employee WHERE ssn*=essn<\/p>\n\n\n\n
\u81ea\u6211\u5408\u4f75<\/strong>
where\u683c\u5f0f\u5927\u81f4\u70ba
SELECT * FROM table1,table1 AS table2 WHERE < table1.column = table2.column><\/strong>
join\u683c\u5f0f\u5927\u81f4\u70ba
SELECT * FROM table1 < join type> table1 AS table2 ON < table1.column = table2.column><\/strong><\/p>\n\n\n\n
\u5217\u51fa\u54e1\u5de5\u540d\u7a31\u53ca\u54e1\u5de5\u7684\u4e3b\u7ba1\u540d\u7a31<\/strong>
\u8cc7\u6599\u8868\u5982\u4e0b
employee(fname,minit,lname,ssn,bdate,address,sex,salary,super_ssn,dno)
\u8a9e\u6cd5\u5982\u4e0b
\u4e0d\u6703\u986f\u793a\u8001\u95c6(\u56e0\u70ba\u8001\u95c6\u6c92\u6709\u4e3b\u7ba1)
SELECT emp.fname,emp.lname,’->’,super.fname,super.lname
FROM employee AS emp, employee AS super
WHERE emp.super_ssn=super.ssn
ps:\u986f\u793a\u8001\u95c6
SELECT emp.fname,emp.lname,’->’,super.fname,super.lname
FROM employee AS emp, employee AS super
WHERE emp.super_ssn*=super.ssn<\/p>\n\n\n\n
\u5c07\u5169\u500bsql\u7684\u7d50\u679c\u5408\u4f75,\u4e0d\u6703\u91cd\u8907\u5217\u51fa<\/p>\n\n\n\n
\u5c07\u5169\u500bsql\u7684\u7d50\u679c\u5408\u4f75,\u82e5\u767c\u751f\u91cd\u8907\u6642\u5247\u6703\u5168\u90e8\u5217\u51fa<\/p>\n\n\n\n
\u5047\u8a2d\u6709\u4ee5\u4e0b\u5169table
srcip\u7684ip\u67091.1.1.2 ,1.1.1.3
dstip\u7684ip\u67091.1.1.1 ,1.1.1.2
ex:
\u57f7\u884csql\u8a9e\u6cd5
select ip from srcip
union
select ip from dstip
\u5247\u7d50\u679c\u5982\u4e0b
1.1.1.1
1.1.1.2
1.1.1.3
ex:
\u57f7\u884csql\u8a9e\u6cd5
select ip from srcip
union all
select ip from dstip
\u5247\u7d50\u679c\u5982\u4e0b
1.1.1.1
1.1.1.2
1.1.1.2
1.1.1.3<\/p>\n\n\n\n
INTERSECT<\/strong>
\u5c07\u5169\u500bsql\u7684\u7d50\u679c\u76f8\u540c\u7684\u5408\u4f75<\/p>\n\n\n\n
\u57f7\u884csql\u8a9e\u6cd5
select ip from srcip
intersect
select ip from dstip
\u5247\u7d50\u679c\u5982\u4e0b
1.1.1.2<\/p>\n\n\n\n
MINUS<\/strong>
\u5c07\u7b2c1\u500bsql\u7684\u7d50\u679c\u6263\u6389\u7b2c\u4e8c\u500bsql\u540c\u6a23\u7684\u7d50\u679c<\/p>\n\n\n\n
\u57f7\u884csql\u8a9e\u6cd5
select ip from srcip
minus
select ip from dstip
\u5247\u7d50\u679c\u5982\u4e0b
1.1.1.3<\/p>\n","protected":false},"excerpt":{"rendered":"