0f4df23290
Some checks failed
kotlin / test (push) Has been skipped
python / test (push) Has been skipped
typescript / test (push) Has been skipped
go / build darwin/amd64 (push) Has been cancelled
go / build linux/amd64 (push) Has been cancelled
go / build windows/amd64 (push) Has been cancelled
go / build darwin/arm64 (push) Has been cancelled
go / build linux/arm64 (push) Has been cancelled
go / build windows/arm64 (push) Has been cancelled
go / test (push) Has been cancelled
go / vuln_check (push) Has been cancelled
84 lines
1.5 KiB
Markdown
84 lines
1.5 KiB
Markdown
# Counting rows
|
|
|
|
```sql
|
|
CREATE TABLE authors (
|
|
id SERIAL PRIMARY KEY,
|
|
hometown text NOT NULL
|
|
);
|
|
|
|
-- name: CountAuthors :one
|
|
SELECT count(*) FROM authors;
|
|
|
|
-- name: CountAuthorsByTown :many
|
|
SELECT hometown, count(*) FROM authors
|
|
GROUP BY 1
|
|
ORDER BY 1;
|
|
```
|
|
|
|
```go
|
|
package db
|
|
|
|
import (
|
|
"context"
|
|
"database/sql"
|
|
)
|
|
|
|
type DBTX interface {
|
|
QueryContext(context.Context, string, ...any) (*sql.Rows, error)
|
|
QueryRowContext(context.Context, string, ...any) *sql.Row
|
|
}
|
|
|
|
func New(db DBTX) *Queries {
|
|
return &Queries{db: db}
|
|
}
|
|
|
|
type Queries struct {
|
|
db DBTX
|
|
}
|
|
|
|
const countAuthors = `-- name: CountAuthors :one
|
|
SELECT count(*) FROM authors
|
|
`
|
|
|
|
func (q *Queries) CountAuthors(ctx context.Context) (int, error) {
|
|
row := q.db.QueryRowContext(ctx, countAuthors)
|
|
var i int
|
|
err := row.Scan(&i)
|
|
return i, err
|
|
}
|
|
|
|
const countAuthorsByTown = `-- name: CountAuthorsByTown :many
|
|
SELECT hometown, count(*) FROM authors
|
|
GROUP BY 1
|
|
ORDER BY 1
|
|
`
|
|
|
|
type CountAuthorsByTownRow struct {
|
|
Hometown string
|
|
Count int
|
|
}
|
|
|
|
func (q *Queries) CountAuthorsByTown(ctx context.Context) ([]CountAuthorsByTownRow, error) {
|
|
rows, err := q.db.QueryContext(ctx, countAuthorsByTown)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer rows.Close()
|
|
items := []CountAuthorsByTownRow{}
|
|
for rows.Next() {
|
|
var i CountAuthorsByTownRow
|
|
if err := rows.Scan(&i.Hometown, &i.Count); err != nil {
|
|
return nil, err
|
|
}
|
|
items = append(items, i)
|
|
}
|
|
if err := rows.Close(); err != nil {
|
|
return nil, err
|
|
}
|
|
if err := rows.Err(); err != nil {
|
|
return nil, err
|
|
}
|
|
return items, nil
|
|
}
|
|
```
|