/// <summary>
/// 获取数量
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="connection"></param>
/// <param name="tableName"></param>
/// <param name="whereExpress">条件表达式</param>
/// <param name="outSqlAction">返回sql语句</param>
/// <returns></returns>
public static async Task <int> CountAsync <TEntity>(this
IDbConnection connection,
string tableName,
Expression <Func <TEntity, bool> > whereExpress,
Action <string> outSqlAction = null)
where TEntity : class, new()
{
if (string.IsNullOrEmpty(tableName))
{
throw new ArgumentNullException(nameof(tableName));
}
var dbType = connection.GetDbType();
var sqlExpression = SqlExpression.Count <TEntity>(dbType, tableName: tableName).Where(whereExpress);
var task = await connection.QueryFirstOrDefaultAsync <int>(sqlExpression.Script, sqlExpression.DbParams);
// 返回sql
outSqlAction?.Invoke(sqlExpression.Script);
return(task);
}
