Working with SQL DBs in Go

Go’s database/sql package — part of the standard library — provides a DB struct that allows us to interact with SQL (relational) databases.

There are 3 methods available for executing queries:

• DB.QueryContext() for SELECT queries that return multiple rows;
• DB.QueryRowContext() for SELECT queries that return a single row;
• DB.ExecContext() for queries that don’t return any rows (e.g. INSERT)

The idiomatic way to execute these queries is with the “context-aware” variants listed above, but there are also variants that don’t accept a context, e.g. DB.Query()

DB.ExecContext()

The function signature is:

func (db *DB) ExecContext(ctx context.Context, query string, args ...any) (Result, error)

where args are placeholder arguments passed to the query.

DB.QueryContext()

The function signature is

func (db *DB) QueryContext(ctx context.Context, query string, args ...any) (*Rows, error)

where args are placeholder arguments passed to the query.

DB.QueryRowContext()

The function signature is

func (db *DB) QueryRowContext(ctx context.Context, query string, args ...any) *Row

where args are placeholder arguments passed to the query.

For some reason I’m not quite sure of, the *Row struct has an error field in it, so this method can return an error — it’s just in the row struct?