A PL/SQL query is a statement used to retrieve data from a database. A PL/SQL subquery is a query that is nested inside another PL/SQL query.
The Oracle PL/SQL Query syntax typically consists of a SELECT clause, followed by a FROM clause, and optionally a WHERE, GROUP BY, and ORDER BY clause. For example:
SELECT * FROM table_name WHERE condition GROUP BY column_name HAVING condition ORDER BY column_name
Below are a list of pl/sql queries that you can use to learn some basic rules about queries.
ANY
The ANY keyword can be used in a query to return all rows from a table that meet a certain condition. For example:
SELECT * FROM table_name WHERE column_name = ANY (value1, value2, value3)
BETWEEN
The BETWEEN keyword can be used in a query to specify a range of values. For example:
SELECT * FROM table_name WHERE column_name BETWEEN value1 AND value2
EXISTS
The EXISTS keyword can be used in a query to check if a row exists in a table. For example:
SELECT * FROM table_name WHERE EXISTS (SELECT column_name FROM another_table WHERE condition)
GROUP BY
The GROUP BY keyword can be used in a query to group rows together. For example:
SELECT * FROM table_name GROUP BY column_name
HAVING
The HAVING keyword can be used in a query to specify a condition for the groups. For example:
SELECT * FROM table_name HAVING column_name = value
IN
The IN keyword can be used in a query to check if a value is in a list of values. For example:
SELECT * FROM table_name WHERE column_name IN (value1, value2, value3)
LIKE
The LIKE keyword can be used in a PL/SQL query to search for a specific pattern. For example:
SELECT * FROM table_name WHERE column_name LIKE '%value%'
ORDER BY
The ORDER BY keyword can be used in a query to sort the results. For example:
SELECT * FROM table_name ORDER BY column_name ASC/DESC
WHERE
The WHERE keyword can be used in a PL/SQL query to specify a condition. For example:
SELECT * FROM table_name WHERE column_name = value1 AND column_name2 = value2