SQL 对版本进行排序遇到的问题

背景

物料存在多个版本，我们每次只需要使用最新的版本

问题

• 问题1：版本使用的是字符串，倒序排序，会导致 版本8 会排在版本11 前面
• 问题2：版本version字符串既有数字字符串，也有字母字符串

解决思路

• 对于数字字符串，需要将其转换成整数，
• 字母字符串则转换成对应的ASCII码值

SQL语句

原本语句

    SELECT 
        material_code AS material_code_in,
        material_name AS material_name_in,
        '' AS material_type_in,
        material_class_small AS material_class_small_in,
        material_class_big AS material_class_big_in,
        erp_code AS erp_code_in,
        version AS version_in,
        unit AS unit_in
    FROM tbl_material_info 
    WHERE material_code IN ('P120','P525A','2070039115')

改写语句

WITH RankedMaterials AS (
    SELECT 
        material_code AS material_code_in,
        material_name AS material_name_in,
        '' AS material_type_in,
        material_class_small AS material_class_small_in,
        material_class_big AS material_class_big_in,
        erp_code AS erp_code_in,
        version AS version_in,
        unit AS unit_in,
        ROW_NUMBER() OVER (
            PARTITION BY material_code 
            ORDER BY 
                CASE 
                    WHEN TRY_CAST(version AS INT) IS NOT NULL THEN TRY_CAST(version AS INT) 
                    ELSE ASCII(SUBSTRING(version, 1, 1)) -- 将字母字符串转换为对应的ASCII码值
                END DESC
        ) AS rn
    FROM tbl_material_info 
    WHERE material_code IN ('P120','P525A','2070039115')
)
SELECT 
    material_code_in,
    material_name_in,
    material_type_in,
    material_class_small_in,
    material_class_big_in,
    erp_code_in,
    version_in,
    unit_in
FROM RankedMaterials
WHERE rn = 1;