How do I get unique results in SQL?

How do I find unique values in a query?

Answer: Open your query in design view. Right-click somewhere in the Query window beside a table (but not on a table) and select Properties from the popup menu. Set the “Unique Values” property to Yes. Then close the property editor by clicking the X in the top right corner.

How do I count unique values in SQL?

The COUNT DISTINCT function returns the number of unique values in the column or expression, as the following example shows. SELECT COUNT (DISTINCT item_num) FROM items; If the COUNT DISTINCT function encounters NULL values, it ignores them unless every value in the specified column is NULL.

What is distinct SQL?

The SQL DISTINCT keyword is used in conjunction with the SELECT statement to eliminate all the duplicate records and fetching only unique records. There may be a situation when you have multiple duplicate records in a table.

Is there a unique function in SQL?

The UNIQUE constraint ensures that all values in a column are different. Both the UNIQUE and PRIMARY KEY constraints provide a guarantee for uniqueness for a column or set of columns. However, you can have many UNIQUE constraints per table, but only one PRIMARY KEY constraint per table. …

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How do I find unique values in a table?

The unique values are fetched when we use the distinct keyword.

  1. SELECT DISTINCT returns only distinct (different) values.
  2. DISTINCT eliminates duplicate records from the table.
  3. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc.
  4. DISTINCT operates on a single column.

Which is faster count (*) or Count 1?

According to this theory COUNT(*) takes all columns to count rows and COUNT(1) counts using the first column: Primary Key. Thanks to that COUNT(1) is able to use index to count rows and it’s much faster.

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 do I count the number of distinct rows in SQL?

To count the number of different values that are stored in a given column, you simply need to designate the column you pass in to the COUNT function as DISTINCT . When given a column, COUNT returns the number of values in that column. Combining this with DISTINCT returns only the number of unique (and non-NULL) values.

How can I get distinct values in SQL without 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.
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What is the use of distinct keyword?

The DISTINCT keyword is used to fetch distinct records from a database table. The DISTINCT clause is basically used to remove duplicates from the result set of a SELECT statement and only selects DIFFERENT values.

What can SQL not do?

The SQL NOT condition (sometimes called the NOT Operator) is used to negate a condition in the WHERE clause of a SELECT, INSERT, UPDATE, or DELETE statement.

How do I make SQL unique?

The syntax for creating a unique constraint using an ALTER TABLE statement in SQL Server is: ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column1, column2, … column_n); table_name.

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