mysql中标量子查询和关联子查询的性能比较

在mysql执行相同的查询操作：

关联子查询：

SELECT a.BranchID,b.orgname
FROM TargetCustomer AS a
JOIN Organization AS b ON a.BranchID=b.orgid;
执行时间：00:00:00:156

标量子查询

SELECT a.branchid,(SELECT orgname FROM Organization AS b WHERE b.orgid=a.branchid) AS branchname
FROM TargetCustomer AS a;
执行时间：00:00:04.087

结论：关联查询的性能要优于标量子查询