MySql： Column 'XXXX' in field list is ambiguous 错误

[Err] 1052 - Column 'XXXX' in field list is ambiguous

例如：

SELECT
    id,
    a.name,
    price,
    `describe`,
    schoolid,
    `subject`
FROM
    tariffpackages a,
    schooluser b
WHERE
    a.schoolid=b.Schoolid

出现错误：

[SQL]SELECT
    id,
    a.name,
    price,
    `describe`,
    schoolid,
    `subject`
FROM
    tariffpackages a,
    schooluser b
WHERE
    a.schoolid=b.Schoolid

[Err] 1052 - Column 'schoolid' in field list is ambiguous

原因是：

tariffpackages表和schooluser表中都有schoolid字段。

解决方法：

SELECT
    id,
    a.name,
    price,
    `describe`,
    a.schoolid,
    `subject`
FROM
    tariffpackages a,
    schooluser b
WHERE
    a.schoolid=b.Schoolid