Quick Answer: Can Rowid Be Duplicate?

How can get second highest salary in MySQL?

SELECT MAX(salary) FROM Employee WHERE Salary NOT IN ( SELECT Max(Salary) FROM Employee); This will return 200 in our case.

SELECT MAX(Salary) From Employee WHERE Salary < ( SELECT Max(Salary) FROM Employee); You can use this SQL query if Interviewer ask you to get second highest salary in MySQL without using LIMIT..

How can I delete duplicate rows?

To delete the duplicate rows from the table in SQL Server, you follow these steps:Find duplicate rows using GROUP BY clause or ROW_NUMBER() function.Use DELETE statement to remove the duplicate rows.

How do I select without duplicates in SQL?

SQL SELECT DISTINCT Statement SELECT DISTINCT returns only distinct (i.e. different) values. The DISTINCT keyword eliminates duplicate records from the results. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. It operates on a single column.

How do you select distinct rows without using distinct?

You can use GROUP BY to select distinct values in SQL without using the DISTINCT keyword….Here’s a solution that does not use the DISTINCT keyword:SELECT t1. … FROM MyTable AS t1.JOIN (SELECT product, consumer FROM MyTable GROUP BY product, consumer)AS t2 ON t1. … GROUP BY t1.

How remove duplicate rows inner join in Oracle?

select table1.id , table2. type , case when row_number() over (partition by table1.id order by table2. type) = 1 then table1. value end as “VALUE” , table2.

How do I delete duplicate records in Oracle SQL Developer?

After “SQL,” enter “select rowid, name from names;.” Delete the duplicate. After “SQL,” enter “delete from names a where rowid > (select min(rowid) from names b where b.name=a.name);” to delete duplicate records. Check for duplicates.

How do I duplicate a row?

Select the rows into which you want to copy the original row or rows. Right-click the selection, and then click “Insert Copied Cells.” Excel inserts the repeated data into the new rows, moving the existing rows down.

How do I count duplicate rows in SQL?

Using GROUP BY clause to find duplicates in a tableFirst, the GROUP BY clause groups the rows into groups by values in both a and b columns.Second, the COUNT() function returns the number of occurrences of each group (a,b).More items…

How do I find duplicate rows in SQL using Rowid?

Use the rowid pseudocolumn. DELETE FROM your_table WHERE rowid not in (SELECT MIN(rowid) FROM your_table GROUP BY column1, column2, column3); Where column1 , column2 , and column3 make up the identifying key for each record. You might list all your columns.

How can I duplicate a row in SQL?

To select duplicate values, you need to create groups of rows with the same values and then select the groups with counts greater than one. You can achieve that by using GROUP BY and a HAVING clause.

How do you remove duplicates without using distinct in SQL?

SQL | Remove Duplicates without DistinctRemove Duplicates Using Row_Number. WITH CTE (Col1, Col2, Col3, DuplicateCount) AS ( SELECT Col1, Col2, Col3, ROW_NUMBER() OVER(PARTITION BY Col1, Col2, Col3 ORDER BY Col1) AS DuplicateCount FROM MyTable ) SELECT * from CTE Where DuplicateCount = 1.Remove Duplicates using group By.

How do you delete one record from duplicates in SQL?

So to delete the duplicate record with SQL Server we can use the SET ROWCOUNT command to limit the number of rows affected by a query. By setting it to 1 we can just delete one of these rows in the table. Note: the select commands are just used to show the data prior and after the delete occurs.

How do I remove duplicate rows from one column?

Remove duplicate valuesSelect the range of cells, or ensure that the active cell is in a table.On the Data tab, click Remove Duplicates .In the Remove Duplicates dialog box, unselect any columns where you don’t want to remove duplicate values. … Click OK, and a message will appear to indicate how many duplicate values were removed.

How can I delete duplicate rows in SQL without using Rowid?

Backup your original table. … Make sure your backup is good and you can restore original table if you. … Create a temporary table with unique records using DISTINCT clause.Delete all records from original table.Insert all records from temporary table into original table.Verify your results and commit your work.

How do I remove duplicates in select query?

The go to solution for removing duplicate rows from your result sets is to include the distinct keyword in your select statement. It tells the query engine to remove duplicates to produce a result set in which every row is unique. The group by clause can also be used to remove duplicates.

What is difference between unique and distinct?

The main difference between unique and distinct is that UNIQUE is a constraint that is used on the input of data and ensures data integrity. While DISTINCT keyword is used when we want to query our results or in other words, output the data.

How prevent duplicate rows in SQL JOIN?

The GROUP BY clause at the end ensures only a single row is returned for each unique combination of columns in the GROUP BY clause. This should prevent duplicate rows being displayed in your results.

How do you delete duplicate records in Oracle record?

It will delete all duplicate rows and keep one original record. Create a temp table with distinct record from master table then delete from master table then again insert from temp table. By this you can delete 4 record and one record is undeleted.