The concept of a "First Row " is only valid if we implement some type of ordering mechanism for the rowset (a key value). How to retrive desired 10/20 records from oracle tables … The PARTITION BY indicates it should restart at 1 every time the value of Val changes and we want to order rows by the smallest value of Kind. WITH ORDERED AS ( SELECT ID , Val , kind , ROW_NUMBER() OVER (PARTITION BY Val ORDER BY Kind ASC) AS rn FROM mytable ) SELECT ID , Val , Kind FROM ORDERED WHERE rn = 1; Basic SELECT statement: Select first 10 records from a table Last update on February 26 2020 08:09:45 (UTC/GMT +8 hours) MySQL Basic Select Statement: Exercise-18 with Solution So, please tell us how to perform the following: 1. The first query uses correlated sub-query to get the top 10 most expensive products. SELECT *FROM yourTableName ORDER BY yourIdColumnName LIMIT 10; in bold it clearly says that oracle will fetch the first n rows (for e.g.) my question is when i do this select /*+first_rows(10)*/ * from emp where deptno=10; This select orders (over (order by empno asc) )the rows: select empno, ename , ROWNUMB from (select empno, ename , row_number() over (order by empno asc) as ROWNUMB from emp) where ROWNUMB between 10 and 30; Examples-- Fetch the first row of T SELECT * FROM T FETCH FIRST ROW ONLY -- Sort T using column I, then fetch rows 11 through 20 of the sorted -- rows (inclusive) SELECT * FROM T ORDER BY I OFFSET 10 ROWS FETCH NEXT 10 ROWS ONLY -- Skip the first 100 rows of T -- If the table has fewer than 101 records, an empty result set is -- returned SELECT * FROM T OFFSET 100 ROWS -- Use of ORDER BY … PostgreSQL v8.3 and later can also use this more standard SQL: SELECT column FROM table FETCH FIRST 10 ROWS ONLY. 03.10.2008 at 05:11PM EET Of course the rows have to be ordered! Next, let's look at what Oracle Database can do conceptually with a top-N query: select * from (select * from t order by unindexed_column) where ROWNUM < :N; To select first 10 elements from a database using SQL ORDER BY clause with LIMIT 10. It works for any Oracle versions, including Oracle 8i or older. Oracle Database has most likely copied the entire table into TEMP and written it out, just to get the first 10 rows. These rows are stored in the temporary table t_s. The syntax is as follows. The FIRST_ROWS hint, which optimizes for the best plan to return the first single row, is retained for backward compatibility and plan stability. The cursor c is a SELECT statement that returns the rowids that contain the word omophagia in sorted order. But, we dont want to have all the rows initially. Now, that is a lot of I/O. for a query. The code loops through the cursor to extract the first 10 rows. 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