The GROUP_CONCAT() function in MySQL is used to concatenate data from multiple rows into one field. This is an aggregate (GROUP BY) function which returns a String value, if the group contains at least one non-NULL value. Otherwise, it returns NULL.
What is the difference between concat and Group_concat in MySQL?
The difference here is while CONCAT is used to combine values across columns, GROUP_CONCAT gives you the capability to combine values across rows. It’s also important to note that both GROUP_CONCAT and CONCAT can be combined to return desired results.
What is limit of Group_concat in MySQL?
The GROUP_CONCAT() function has a default length of 1024 characters, which is controlled by the global variable group_concat_max_len . If the joined values length is greater than the group_concat_max_len value, then the result string will be truncated.
What is aggregation in MySQL?
MySQL’s aggregate function is used to perform calculations on multiple values and return the result in a single value like the average of all values, the sum of all values, and maximum & minimum value among certain groups of values.
What is opposite of Group_concat in MySQL?
That operation is called pivoting / unpivoting.
What is Group_concat_max_len?
As MySQL Blog by @Shlomi Noach Here group_concat_max_len : This parameter limits the maximum text length of a GROUP_CONCAT concatenation result. It defaults to 1024 .
What is the difference between concat () concat with and Concat_ws ()?
Both CONCAT() and CONCAT_WS() functions are used to concatenate two or more strings but the basic difference between them is that CONCAT_WS() function can do the concatenation along with a separator between strings, whereas in CONCAT() function there is no concept of the separator.
Does Group_concat have a limit?
MySQL and GROUP_CONCAT() maximum length
However, the maximum length of the result of this function is 1024 characters.
What is STD in MySQL?
MySQL STD() function returns the population standard deviation of expression. It returns NULL if no matching row is found. Syntax: STD(expr);
What is aggregate function example?
An aggregate function performs a calculation on multiple values and returns a single value. For example, you can use the AVG() aggregate function that takes multiple numbers and returns the average value of the numbers.
What are the 6 aggregate functions of SQL?
SQL Aggregate Functions
- AVG – calculates the average of a set of values.
- COUNT – counts rows in a specified table or view.
- MIN – gets the minimum value in a set of values.
- MAX – gets the maximum value in a set of values.
- SUM – calculates the sum of values.