Tag:Duplicate record

  • Three methods of deleting duplicate records in Oracle query

    Time:2020-11-14

    For example, there is a personnel table (Table Name: peosons)If you want to record the name, ID number and address of the three fields exactly the same, Copy codeThe code is as follows: select p1.*   from persons  p1,persons  p2   where p1.id<>p2.id   and  p1.cardid = p2.cardid and p1.pname = p2.pname and p1.address = p2.address The above […]

  • [Oracle] – set operation: Union, union all

    Time:2020-10-13

    Three types of set operations are provided in Oracle: Union, intersect and minus Union: Union,Duplicate records are displayed only once。 Union all: Union all, display all record information. Intersect: find intersection Minus: returns the difference set of two query results ​ Let’s introduce the set operation of Oracle 1、 Data preparation Create emp10 table based […]

  • Methods of querying and deleting duplicate records in MySQL

    Time:2020-7-30

      preface This paper mainly introduces the methods of querying and deleting duplicate records in mysql, and shares them for your reference. Here’s a detailed introduction: Find all records with duplicate Titles: 1 select title,count(*) as count from user_table group by title having count>1; 1 SELECT * FROM t_info a WHERE ((SELECT COUNT(*) FROM t_info WHERE Title = a.Title) > 1) ORDER BY Title DESC 1、 Find duplicate records 1. […]

  • [SQL interview question 1] MySQL or Oracle Database

    Time:2020-7-6

    There are three interview questions as follows: Create two tables: CREATE TABLE CUSTOMERS ( ID NUMBER(2), NAME VARCHAR2(10) ); CREATE TABLE ORDERS ( ID NUMBER(2), CUSTOMERID NUMBER(2) ); SELECT * FROM CUSTOMERS; INSERT INTO CUSTOMERS VALUES(1,’JOE’); INSERT INTO CUSTOMERS VALUES(2,’HENRY’); INSERT INTO CUSTOMERS VALUES(3,’SAM’); INSERT INTO CUSTOMERS VALUES(4,’MAX’); SELECT * FROM ORDERS; INSERT INTO ORDERS […]

  • Loading feature master data to automatically delete duplicate key values

    Time:2020-2-17

    When extracting the attribute data of information object, an error is found. After checking, it is found that the data source has duplicate key values Originally, I wanted to delete duplicates in the start routine and found that DTP already has this function. Check [process duplicate key value] in DTP [update] After re execution, duplicate […]

  • SQL deletes duplicate records in tables

    Time:2019-10-13

    When we encounter the problem of duplicate records in the table, it is the fastest to delete SQL directly, so we should not copy it slowly to find it manually in the excel table. Following sql, find the duplicate record and the record with the lowest ID value in the duplicate record (the ID in […]

  • Method Sharing of Deleting Duplicate Records in SQL Server 2008

    Time:2019-9-12

    Now let’s see how to delete these records in SQL SERVER 2008. First, we can simulate some simple duplicate records: Copy codeThe code is as follows: Create Table dbo.Employee ( [Id] int Primary KEY , [Name] varchar(50), [Age] int, [Sex] bit default 1 ) Insert Into Employee ([Id] , [Name] , [Age] , [Sex] ) […]