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package query
import (
"context"
"database/sql"
"errors"
"fmt"
)
// Count returns the number of rows in the given table.
func Count(ctx context.Context, tx *sql.Tx, table string, where string, args ...any) (int, error) {
stmt := fmt.Sprintf("SELECT COUNT(*) FROM %s", table)
if where != "" {
stmt += fmt.Sprintf(" WHERE %s", where)
}
rows, err := tx.QueryContext(ctx, stmt, args...)
if err != nil {
return -1, err
}
defer func() { _ = rows.Close() }()
// Ensure we read one and only one row.
if !rows.Next() {
return -1, errors.New("no rows returned")
}
var count int
err = rows.Scan(&count)
if err != nil {
return -1, errors.New("failed to scan count column")
}
if rows.Next() {
return -1, errors.New("more than one row returned")
}
err = rows.Err()
if err != nil {
return -1, err
}
return count, nil
}
// CountAll returns a map associating each table name in the database
// with the total count of its rows.
func CountAll(ctx context.Context, tx *sql.Tx) (map[string]int, error) {
tables, err := SelectStrings(ctx, tx, "SELECT name FROM sqlite_master WHERE type = 'table'")
if err != nil {
return nil, fmt.Errorf("Failed to fetch table names: %w", err)
}
counts := map[string]int{}
for _, table := range tables {
count, err := Count(ctx, tx, table, "")
if err != nil {
return nil, fmt.Errorf("Failed to count rows of %s: %w", table, err)
}
counts[table] = count
}
return counts, nil
}
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