Snowflake Query

An SQL statement used to query the database. The query can be a simple query or a complex query. A complex query has nested SQL statements. Prepared SQL queries can be constructed by using substitution variables or substitution parameters of the form ?<fieldname> in the query statement.

Example:

 select * from student where name like ?name; 
					 

Each substitution variable identifies an input parameter whose mapped value is substituted into the substitution variable at runtime. The substitution variable can be reused for the same input parameter elsewhere in the query. Input parameters used in the WHERE clause, output parameters used in the SELECT clause, and their corresponding type information is automatically fetched from the database using the selected connection for the entered query. Input and output fields on the Input and Output tabs of the activity are also automatically generated. You must include the semicolon (;) at the end of the query. To indicate the end of the query, a semicolon is expected at the end. A missing semicolon at the end of the query causes the query to be unresponsive.

Examples of simple and complex queries:

Simple query

SELECT * FROM employee; 

In this query, the output fields are generated from the table employee's column information.

SELECT description, url, name FROM webpages
WHERE name = ?name and id > ?id ORDER BY name;

For this query, output fields are generated for description, url, and name. Input fields are generated for name (varchar) and id (numeric). Also, the mapped values for the name and id fields are substituted into the ?name and ?id substitution variables at runtime.

Nested query

SELECT firstname, lastname, total_quantity
FROM (SELECT buyerid, sum(qtysold) total_quantity
FROM sales
GROUP BY buyerid
ORDER BY total_quantity desc limit 10) Q, users
WHERE Q.buyerid = userid
ORDER BY Q.total_quantity desc;