Mis on ettevalmistatud päringud (prepared statements)?

Prepared statements are a mechanism for working with databases, where the SQL query is compiled and optimized once, and then can be executed multiple times with different parameters.

Advantages:

• Increased performance when calling the same query repeatedly.
• Security — protection against SQL injections, as parameters are passed separately from the query text.
• Convenience — parameters are automatically inserted, no need to manually escape values.

In Go, a prepared query is created using the Prepare method of the *sql.DB or *sql.Tx object:

stmt, err := db.Prepare("SELECT name FROM users WHERE id = ?")
if err != nil {
    log.Fatal(err)
}
defer stmt.Close()

var name string
err = stmt.QueryRow(1).Scan(&name)
if err != nil {
    log.Fatal(err)
}
fmt.Println(name)

This way, the query is compiled once, and can be called multiple times with different parameters.