How do I delete all records except one in SQL?

4 Answers

  1. Select the record with id 1800 into a temporary table.
  2. Drop the original table.
  3. Copy the data from the temp table into the full table.

How do I remove all duplicates but keep only one in SQL?

  1. Create a New Table With Unique Values Copied From Original Table.
  2. Use Temporary Table to Fill Original Table With Unique Rows.
  3. Add Unique Constraint and Copy Unique Rows to Original Table.
  4. Remove Duplicates and Keep Row With Lowest ID.
  5. Remove Duplicates and Keep Row With Highest ID.

How do I delete duplicate rows but keep one?

Remove all duplicates but keep only one with Remove Duplicates function

  1. Select the data list you need, and click Data > Remove Duplicates.
  2. Then in Remove Duplicates dialog, check the column name that you want to remove duplicates from, and if your data has header, check My data has headers option, too.
  3. Click OK.

Can delete single or multiple records from a table?

The DELETE Statement in SQL is used to delete existing records from a table. We can delete a single record or multiple records depending on the condition we specify in the WHERE clause.

How do I ignore duplicate records in SQL?

Use the INSERT IGNORE command rather than the INSERT command. If a record doesn’t duplicate an existing record, then MySQL inserts it as usual. If the record is a duplicate, then the IGNORE keyword tells MySQL to discard it silently without generating an error.

How do I eliminate duplicates in SQL?

  1. 1) First identify the rows those satisfy the definition of duplicate and insert them into temp table, say #tableAll .
  2. 2) Select non-duplicate(single-rows) or distinct rows into temp table say #tableUnique.
  3. 3) Delete from source table joining #tableAll to delete the duplicates.

How do I ensure no duplicates in SQL?

3 Answers

  1. Open SQL Server Management Studio.
  2. Expand the Tables folder of the database where you wish to create the constraint.
  3. Right-click the table where you wish to add the constraint and click Design.
  4. In Table Designer, click on Indexes/Keys.
  5. Click Add.
  6. Choose Unique Key in the Type drop-down list.

How do you remove duplicates without using distinct?

Below are alternate solutions :

  1. Remove 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.
  2. Remove Duplicates using group By.

How can I delete duplicate records from a table in SQL?

How do I eliminate duplicate rows in SQL?

To delete the duplicate rows from the table in SQL Server, you follow these steps:

  1. Find duplicate rows using GROUP BY clause or ROW_NUMBER() function.
  2. Use DELETE statement to remove the duplicate rows.

How do I delete multiple records?

Deleting multiple records

  1. Create (or open) a table report that contains the records you want to delete.
  2. Select More, then select Delete these records. A window appears to confirm the deletion.
  3. Select the Delete button to confirm, which closes the confirmation window.

What is the difference between truncate and delete?

The DELETE statement removes rows one at a time and records an entry in the transaction log for each deleted row. TRUNCATE TABLE removes the data by deallocating the data pages used to store the table data and records only the page deallocations in the transaction log.