To delete the odd rows of a table in Oracle, you can use a subquery within a DELETE statement. You can achieve this by using the MOD function to determine whether a row is odd or even, and then deleting the odd rows based on this condition. Here is an example query that demonstrates this logic:
DELETE FROM your_table WHERE rowid IN ( SELECT rowid FROM ( SELECT rowid, row_number() over (order by some_column) as rn FROM your_table ) WHERE MOD(rn, 2) != 0 );
In this query, replace "your_table" with the name of your table and "some_column" with the column you want to use for ordering the rows. This query will delete all the odd rows from the table based on the ordering specified.
What is the most effective method for deleting odd rows in Oracle tables?
One effective method for deleting odd rows in Oracle tables is to use a combination of rowid and modulo operation to identify and delete the odd rows. Here is an example SQL query that demonstrates this approach:
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DELETE FROM your_table WHERE MOD(ROWNUM, 2) = 1; |
In this query, the ROWNUM pseudo-column is used to assign a unique row number to each row in the table. The MOD function is then used to calculate the remainder when dividing the row number by 2. Since odd numbers have a remainder of 1 when divided by 2, the condition MOD(ROWNUM, 2) = 1 will select all odd rows in the table for deletion.
It is important to note that deleting rows based on ROWNUM can be unpredictable if there are ongoing transactions or if the table is being actively modified. Additionally, make sure to backup the data before performing any delete operation to avoid unintended data loss.
How do you delete rows with odd row numbers in Oracle?
You can delete rows with odd row numbers in Oracle by using the following SQL query:
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DELETE FROM your_table WHERE MOD(your_primary_key_column, 2) <> 0; |
In this query, replace your_table with the name of your table and your_primary_key_column with the name of your primary key column. The MOD function is used to calculate the remainder when dividing the primary key column values by 2, and then deletes rows where the remainder is not equal to 0 (i.e., odd row numbers).
What is the SQL query to delete rows with odd record numbers in Oracle?
In Oracle, you can delete rows with odd record numbers by using the following SQL query:
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DELETE FROM your_table WHERE MOD(rownum, 2) <> 0; |
Replace your_table with the name of your table. This query uses the MOD function to check if the rownum is odd or even, where MOD(rownum, 2) returns the remainder of the division of rownum by 2. The <> operator is used to select only the rows with odd record numbers, and then those rows are deleted.
