1. 有条款:
拥有子句基本上就像带有 GROUP BY 子句的聚合函数。使用 HAVING 子句代替 WHERE 与聚合函数。而GROUP BY子句将具有相同值的行分组为汇总行。 have 子句与 where 子句一起使用,以查找具有特定条件的行。总是在 group By 子句之后使用ifying 子句。
SELECT COUNT (SALARIES) AS COUNT_SALARIES, EMPLOYEES
FROM EMPLOYEES
GROUP BY SALARIES
HAVING COUNT(SALARIES) > 1;
2. 按条款分组:
GROUP BY 子句通常与聚合函数(MAX、SUM、AVG)一起使用,以按一列或多列对结果进行分组,或者简单地说,我们可以说 GROUP BY 子句与 SELECT 语句配合使用来排列所需的数据成组。
GROUP BY 语句对具有相同值的行进行分组。该语句用在 where 子句之后。此语句通常与某些聚合函数一起使用,例如 SUM、AVG、COUNT atc。按一列或多列对结果进行分组。
SELECT COUNT (SALARIES) AS COUNT_SALARIES, EMPLOYEES
FROM EMPLOYEES
GROUP BY SALARIES;
Have 子句和 Group by 子句的区别:
S.No. | Having Clause | GroupBy Clause |
---|---|---|
1. | It is used for applying some extra condition to the query. | The groupby clause is used to group the data according to particular column or row. |
2. | Having cannot be used without groupby clause. | groupby can be used without having clause with the select statement. |
3. | The having clause can contain aggregate functions. | It cannot contain aggregate functions. |
4. | It restrict the query output by using some conditions | It groups the output on basis of some rows or columns. |