Add count method

src/helpers/DatabaseHelper.ts

@@ -21,6 +21,11 @@ export interface QueryInformation {
 	limit ?: number,
 }
 
+export interface CountQueryInformation {
+	table: string,
+	where ?: Object
+}
+
 export class DatabaseHelper {
 
 	private static connection : Connection;
@@ -188,4 +193,40 @@ export class DatabaseHelper {
 			});
 		})
 	}
+
+	/**
+	 * Perform a COUNT query on the database
+	 * 
+	 * @param info Information about the count query
+	 */
+	static async Count(info: CountQueryInformation) : Promise<number> {
+		
+		let sql = "SELECT COUNT(*) as count FROM " + info.table;
+		let args = [];
+
+		if(info.where) {
+			sql += " WHERE ";
+
+			for (const key in info.where) {
+				if (info.where.hasOwnProperty(key)) {
+					const value = info.where[key];
+					sql += "AND " + key + " = ? ";
+					args.push(value);
+				}
+			}
+
+			sql = sql.replace("WHERE AND", "WHERE");
+		}
+
+		return await new Promise((r, e) => {
+			this.connection.query(sql, args, (err, results, f) => {
+				if(err){
+					e(err);
+					return;
+				}
+
+				r(results[0].count);
+			})
+		});
+	}
 }