distinct 必须放在select 后面第一位

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本文介绍了在SQL查询中使用DISTINCT关键字的基本规则。正确的用法是在SELECT子句中将其置于首位，确保去除重复记录。通过对比正确与错误示例，帮助读者理解如何避免常见错误。

distinct 必须放在select 后面第一位

例：正确例子

SELECT distinct t1.school_id,'107', '校长办公室', '0', '2', '', '', 1,
 NULL, NULL, NULL, NULL, NULL, 1, NULL from edu_cloud_school t1 
left join edu_cloud_department t2 
on t1.school_id=t2.school_id where t2.school_id is null

错误例子：

SELECT '107', '校长办公室', '0', '2', '', '', 1, NULL, NULL,
 NULL, NULL, NULL, 1, NULL from edu_cloud_school t1，distinct t1.school_id
left join edu_cloud_department t2 
on t1.school_id=t2.school_id where t2.school_id is null