How do I get distinct records in SQL?
SQL SELECT DISTINCT Explanation
SELECT DISTINCT returns only unique (i.e. distinct) values. SELECT DISTINCT eliminates duplicate values from the results. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. DISTINCT operates on a single column.
What is distinct in SQL with examples?
SELECT DISTINCT returns only distinct (different) values. DISTINCT eliminates duplicate records from the table. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. DISTINCT operates on a single column.
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Example: DISTINCT Clause handles NULL Values
- SELECT DISTINCT fruit_id.
- FROM fruits.
- ORDER BY category_id;
How does distinct work in SQL?
When only one expression is provided in the DISTINCT clause, the query will return the unique values for that expression. When more than one expression is provided in the DISTINCT clause, the query will retrieve unique combinations for the expressions listed. In SQL, the DISTINCT clause doesn’t ignore NULL values.
How can I get distinct values of all columns in SQL?
To get unique or distinct values of a column in MySQL Table, use the following SQL Query. SELECT DISTINCT(column_name) FROM your_table_name; You can select distinct values for one or more columns. The column names has to be separated with comma.
Why distinct is bad in SQL?
The fact that the resultset has duplicates is frequently (though not always) the result of a poor database design, an ineffective query, or both. In any case, issuing the query without the DISTINCT keyword yields more rows than expected or needed so the keyword is employed to limit what is returned to the user.
How do you eliminate duplicate rows in SQL query without distinct?
Below are alternate solutions :
- 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.
- Remove Duplicates using group By.
Why distinct is used in 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.
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 is difference between unique and distinct in SQL?
The UNIQUE keyword in SQL plays the role of a database constraint; it ensures there are no duplicate values stored in a particular column or a set of columns. On the other hand, the DISTINCT keyword is used in the SELECT statement to fetch distinct rows from a table.
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.
What is distinct query?
Introduction to SQL Server SELECT DISTINCT clause
The query returns only distinct values in the specified column. In other words, it removes the duplicate values in the column from the result set. … In other words, the DISTINCT clause treats all NULL “values” as the same value.
Can we use distinct and count together in SQL?
Yes, you can use COUNT() and DISTINCT together to display the count of only distinct rows. SELECT COUNT(DISTINCT yourColumnName) AS anyVariableName FROM yourTableName; … If you do not use DISTINCT, then COUNT() function gives the count of all rows.
Is group by or distinct faster?
DISTINCT creates a temporary table and uses it for storing duplicates. GROUP BY does the same, but sortes the distinct results afterwards. is faster, if you don’t have an index on profession . All of the answers above are correct, for the case of DISTINCT on a single column vs GROUP BY on a single column.
Which SQL keyword is used to retrieve a maximum value?
MAX() is the SQL keyword is used to retrieve the maximum value in the selected column.