How do you write a query in PL SQL?
PL/SQL SELECT INTO examples
- First, declare a variable l_customer_name whose data type anchors to the name columns of the customers table.
- Second, use the SELECT INTO statement to select value from the name column and assign it to the l_customer_name variable.
- Third, show the customer name using the dbms_output.
Which of the following are valid SQL statements inside PL SQL block?
SQL Pseudocolumns. PL/SQL recognizes the SQL pseudocolumns: CURRVAL , LEVEL , NEXTVAL , ROWID , and ROWNUM . In PL/SQL, pseudocolumns are only allowed in SQL queries, not in INSERT / UPDATE / DELETE statements, or in other PL/SQL statements such as assignments or conditional tests.
How is a function used in PL / SQL?
Functions in PL/SQL. A function can be used as a part of SQL expression i.e. we can use them with select/update/merge commands. One most important characteristic of a function is that unlike procedures, it must return a value. Syntax to create a function:
When to substitute PL / pgSQL for the rest of the query?
PL/pgSQL variables will be substituted into the rest of the query, and the plan is cached, just as described above for commands that do not return rows. This works for SELECT, INSERT / UPDATE / DELETE with RETURNING, and utility commands that return row-set results (such as EXPLAIN ).
How to write a PERFORM statement in PostgreSQL?
To do this in PL/pgSQL, use the PERFORM statement: This executes query and discards the result. Write the query the same way you would write an SQL SELECT command, but replace the initial keyword SELECT with PERFORM. For WITH queries, use PERFORM and then place the query in parentheses.
How to create a function in PostgreSQL SQL?
1) Creating a function using pgAdmin. First, launch the pgAdmin tool and connect to the dvdrental sample database. Second, open the query tool by selecting Tools > Query Tool. Third, enter the above code int the query tool and click the Execute button to create the get_film_count function.