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mysql - 如何从多个连接表MySQL中选择不同的最大值

转载 作者:行者123 更新时间:2023-11-29 11:31:07 25 4
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这是我当前选择数据的查询:

select a.No_Registrasi, a.Nama_CTKI, b.Nama_Negara, c.ID_Rad, d.ID_Lab
FROM tb_registrasi a
JOIN tb_negara_tujuan b
ON a.ID_Negara = b.ID_Negara
JOIN tb_radiologi c
ON a.No_Registrasi = c.No_Registrasi
JOIN tb_laboratorium d
ON a.No_Registrasi = d.No_Registrasi

结果如下:
query result

我如何区分这些 ID_Rad 和 ID_Lab,我需要每个 ID_Rad 和 ID_Lab 的最大值,所以它会像这样:
result

最佳答案

使用GROUP BYMAX,试试这个;)

select a.No_Registrasi, a.Nama_CTKI, b.Nama_Negara, CONCAT('RA-', MAX(substring(c.ID_Rad, 4) + 0)) AS ID_Rad, CONCAT('Lab-',MAX(substring(d.ID_Lab, 5) + 0)) AS Id_Lab
FROM tb_registrasi a
JOIN tb_negara_tujuan b
ON a.ID_Negara = b.ID_Negara
JOIN tb_radiologi c
ON a.No_Registrasi = c.No_Registrasi
JOIN tb_laboratorium d
ON a.No_Registrasi = d.No_Registrasi
GROUP BY a.No_Registrasi, a.Nama_CTKI, b.Nama_Negara

关于mysql - 如何从多个连接表MySQL中选择不同的最大值,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37408182/

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