- What does count (*) mean?
- Which is better distinct or group by in SQL Server?
- What is difference between unique and distinct?
- Can we use distinct and group by together?
- Does Count distinct count nulls?
- How can I get distinct values in SQL without distinct?
- What is the difference between count and count distinct?
- Does count in SQL counts null?
- How is distinct count calculated?
- Can we use distinct in having clause?
- How do I count distinct values in SQL?
- How do you use distinct?
- How do I get distinct rows in SQL?
- Can we have count and distinct together in SQL?
- What is a distinct count?

## What does count (*) mean?

count(*) means it will count all records i.e each and every cell BUT.

count(1) means it will add one pseudo column with value 1 and returns count of all records..

## Which is better distinct or group by in SQL Server?

While DISTINCT better explains intent, and GROUP BY is only required when aggregations are present, they are interchangeable in many cases. Same operators, same number of reads, negligible differences in CPU and total duration (they take turns “winning”).

## 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.

## Can we use distinct and group by together?

SELECT DISTINCT can be used to give distinct values. Use it to remove duplicate records and it can be used with aggregate function as well. … Select group by can be used to get data from different columns and group into one or more column. This can also be applied with aggregate function.

## Does Count distinct count nulls?

COUNT(expression) like all aggregate functions, can take an optional DISTINCT clause. The DISTINCT clause counts only those columns having distinct (unique) values. COUNT DISTINCT does not count NULL as a distinct value. … The ALL keyword counts all non-NULL values, including all duplicates.

## How can I get distinct values in SQL without distinct?

SQL | Remove Duplicates without DistinctRemove 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 self Join. … Remove Duplicates using group By.

## What is the difference between count and count distinct?

Count would show a result of all records while count distinct will result in showing only distinct count. For instance, a table has 5 records as a,a,b,b,c then Count is 5 while Count distinct is 3.

## Does count in SQL counts null?

Using COUNT()will count the number of non-NULL items in the specified column (NULL fields will be ignored). The reason this will work is because when there is no “ELSE” in a CASE statement any row not meeting the criteria is treated as a NULL.

## How is distinct count calculated?

You can use the combination of the SUM and COUNTIF functions to count unique values in Excel. The syntax for this combined formula is = SUM(IF(1/COUNTIF(data, data)=1,1,0)). Here the COUNTIF formula counts the number of times each value in the range appears. The resulting array looks like {1;2;1;1;1;1}.

## Can we use distinct in having clause?

4 Answers. The condition in the HAVING clause cannot include a DISTINCT or UNIQUE aggregate expression. The HAVING clause is evaluated before the SELECT – so the server doesn’t yet know about that alias.

## How do I count distinct values 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 do you use distinct?

SQL SELECT DISTINCT Statement SELECT DISTINCT returns only distinct (i.e. different) values. The DISTINCT keyword eliminates duplicate records from the results. DISTINCT can be used with aggregates: COUNT, AVG, MAX, etc. It operates on a single column.

## How do I get distinct rows in SQL?

To do this, you use the SELECT DISTINCT clause as follows: SELECT DISTINCT column_name FROM table_name; 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.

## Can we have count and distinct together in SQL?

We can use SQL Count Function to return the number of rows in the specified condition. The syntax of the SQL COUNT function: COUNT ([ALL | DISTINCT] expression); By default, SQL Server Count Function uses All keyword.

## What is a distinct count?

The COUNT DISTINCT function returns the number of unique values in the column or expression, as the following example shows. … If every column value is NULL, the COUNT DISTINCT function returns zero (0).