(2,2),(3,3),(4,4); Query OK, 4 rows affected Records: 4 Duplicates: 0 Warnings: 0 obclient> SELECT * FROM tbl1; +---+---+ | COL1 | COL2 | +---+---+ | 1 | 1 | | 2 | 2 | | 3 | 3 | | 4 | 4 | +---+---+ 4 rows in set 单表删除:删除 col1=2 ...
(2,2),(3,3),(4,4); Query OK, 4 rows affected Records: 4 Duplicates: 0 Warnings: 0 obclient> SELECT * FROM tbl1; +---+---+ | COL1 | COL2 | +---+---+ | 1 | 1 | | 2 | 2 | | 3 | 3 | | 4 | 4 | +---+---+ 4 rows in set 单表删除:删除 col1=2 ...
而truncate的操作在MySQL是一个很快的操作,数据转瞬即逝,在Oracle中有一些差别,可能这些数据还有恢复的可能。 比如我们在Oracle端创建一个表空间,创建两个表test_del,test_tru; 创建表空间 create tablespace test_data datafile '/U01/app/oracle/oradata/newtest2/test_data.dbf' size 10M autoextend on; 创建...
If there are many duplicates, this can take a long time. Luckily Oracle Database has many tricks to help youdelete rows faster. How to Prevent More Duplicates You've gone to all the effort of removing the duplicates. You're feeling good. But a week later a new ticket comes in: "Pleas...
Records: 1998067 Duplicates: 0 Warnings: 0这个时候我们来查看对应的文件,在MySQL中通用的方式,对于每个表会对应单独的数据文件和配置文件。 我们可以看到存在4个新的文件,大小都是一样的。 -rw-rw--- 1 mysql mysql 9545 Nov 22 09:52 test_del.frm -...
Records: 1998067 Duplicates: 0 Warnings: 0 创建test_tru > create table test_tru select *from t_fund_info; Query OK, 1998067 rows affected (35.21 sec) Records: 1998067 Duplicates: 0 Warnings: 0这个时候我们来查看对应的文件,在MySQL中通用的方式,对于每个表会对应单独的数据文件和配置文件。
[ASC | DESC], ...]12[HAVING where_definition]13[ORDER BY {unsigned_integer | col_name | formula} [ASC | DESC],...]14[LIMIT [offset,]rows|rows OFFSET offset]15[PROCEDURE procedure_name(argument_list)]16[FOR UPDATE | LOCK IN SHARE MODE]]1718SELECT用于检索从一个或多个表中选取出的...
我负责的有几个系统随着业务量的增长,存储在MySQL中的数据日益剧增,我当时就想现在的业务方不讲武德,搞偷袭,趁我没反应过来把很多表,很快,很快啊都打到了亿级别,我大意了,没有闪,这就导致跟其Join的表的SQL变得很慢,对的应用接口的response time也变长了,影响了用户体验。
In the case of an extract, the source system might be able to fix the extract or remove duplicates before you ingest the file. This is more efficient in multiple ways. It uses fewer network resources and also simplifies your ETL process. And generally, the data owner will understand the da...
name(name),addindexidx_phone(phone);QueryOK,0rowsaffected(6.00sec)Records:0Duplicates:0Warnings:...