In SQL, the HAVING
clause can be used to specify a search condition for a group or an aggregate.
The HAVING
clause is typically used with the GROUP BY
clause. In cases where it’s not, there is an implicit single, aggregated group.
In SQL, the HAVING
clause can be used to specify a search condition for a group or an aggregate.
The HAVING
clause is typically used with the GROUP BY
clause. In cases where it’s not, there is an implicit single, aggregated group.
The SELECT
statement is almost without doubt, the most commonly used statement in SQL.
The SELECT
statement is used for retrieving data from the database. You can specify which rows you want returned, and which columns.
In SQL, the GROUP BY
clause can be used to divide the results of a query into groups of rows.
This is usually done in order to perform one or more aggregations on each group.
Continue readingThe ORDER BY
clause is commonly used in SQL to sort the results of a query.
It allows you to specify the order in which the results are returned.
You can specify whether the results are sorted in ascending order or descending order. You can also specify multiple columns for sorting.
Continue readingIn SQL, the greater than operator (>
) compares two expressions and returns TRUE
if the left operand has a value higher than the right operand; otherwise, it returns FALSE
.
In SQL, the greater than or equal to operator (>=
) compares two expressions and returns TRUE
if the left operand has a value greater than or equal to the right operand; otherwise, it returns FALSE
.
In SQL, the less than or equal to operator (<=
) compares two expressions and returns TRUE
if the left operand has a value lower than or equal to the right operand; otherwise, the result is FALSE
.
You can use it to determine whether a value is less than or equal to another value.
Continue readingIn SQL, the less than operator (<
) compares two expressions and returns TRUE
if the left operand has a value lower than the right operand; otherwise, the result is FALSE
.
In SQL, the not equal to operator (<>
) compares the non-equality of two expressions. That is, it tests whether one expression is not equal to another expression.
If either or both operands are NULL
, NULL
is returned.
SQL also has another not equal to operator (!=
), which does the same thing. Which one you use may depend on your DBMS, which one you’re the most comfortable using, and perhaps also whether your organisation has any coding conventions that dictate which one should be used.
In SQL, the not equal to operator (!=
) compares the non-equality of two expressions. That is, it tests whether one expression is not equal to another expression.
If either or both operands are NULL
, NULL
is returned.
SQL also has another not equal to operator (<>
), which does the same thing. Which one you use may depend on your DBMS, which one you’re the most comfortable using, and perhaps also whether your organisation has any coding conventions that dictate which one should be used.