云和恩墨技术总监,Oracle ACE Director,ACOUG 核心专家 只要增加了DISTINCT关键字,Oracle就会对随后跟着的所有字段进行排序去重。以前也经常发现由于开发人员对SQL不是很理解,在SELECT列表的20多个字段前面添加了DISTINCT,造成查询的执行异常缓慢,基本上很难在ORA-1555错误出现之前得到查询的结果,甚至有些SQL会产生ORA-7445...
【SQL】SQL中distinct的用法在表中，可能会包含重复值。这并不成问题，不过，有时您也许希望仅仅列出不...
Oracle 测试表 SQL>createtablesex(sexchar(1), otherinfo varchar2(64));Tablecreated. 测试数据 SQL>insertintosexselect'm', rownum||'this is test'fromdualconnectbylevel<=10000001;10000001rowscreated.SQL>commit;Commitcomplete.SQL>insertintosexselect'w', rownum||'this is test'fromdualconnectbylevel...
Multiple rows update in oracle sql using for loop, 2 Answers. Sorted by: 3. You can achieve this behavior without looping: UPDATE project SET paymentterm = (SELECT peymentterm FROM temp_project WHERE project.pid = temp_project.pid) WHERE pid IN (SELECT pid FROM temp_project) Share. ...
“Unable to enlist in the transaction” with Oracle linked server from MS SQL Server [<Name of Missing Index, sysname,>] in non clustered index [Execute SQL Task] Error: The value type (__ComObject) can only be converted to variables of type Object. [ODBC Driver Manager] Data source nam...
“Unable to enlist in the transaction” with Oracle linked server from MS SQL Server [<Name of Missing Index, sysname,>] in non clustered index [Execute SQL Task] Error: The value type (__ComObject) can only be converted to variables of type Object. [ODBC Driver Manager] Data source nam...
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acl c cst distinct group IN IS nc OR oracle rac st 优化2020-12-16 上传大小:47KB 所需:34积分/C币 oracle数据库sql优化 针对oracle数据库的sql语句优化。 上传者:violetlove时间:2009-09-22 oracle-distinct-的使用方法.doc oracle-distinct-的使用方法.doc ...
SQL is a language with a syntax all its own, consisting of statements, clauses, and other pieces of code such as operators that establish parameters for limiting the query. An SQL statement is a complete piece of code that goes to a database management system, or DBMS, in order to perfo...
SQL 语句可返回唯一不同的值 A. UNIQUE是完整性约束里的一种,如果某列的值需要是唯一的那么就添加UNIQUE约束 Distinct是在查询时用的,若在SELECT的列 分享1赞 java吧 万马奔骋 oracle字段去重复oracle 怎么给除了主键之外的其他字段去重复,得到的结果就是除了主键之外,其他字段一起不重复,但是 分享1赞 niit吧 ...