SQL sever根据身份证判断性别函数

1. 基本查询示例

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-- 假设表名为 users，身份证字段名为 id_card
SELECT 
    id_card,
    SUBSTRING(id_card, 17, 1) AS 第17位, -- 截取第17位
    CASE 
        WHEN CAST(SUBSTRING(id_card, 17, 1) AS INT) % 2 = 1 
        THEN '男' 
        ELSE '女' 
    END AS 性别
FROM users
WHERE LEN(id_card) = 18; -- 确保是18位身份证

2. 完整函数封装

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-- 创建判断性别的函数
CREATE FUNCTION dbo.GetGenderByIdCard(@id_card VARCHAR(18))
RETURNS VARCHAR(2)
AS
BEGIN
    DECLARE @gender VARCHAR(2)
    
    IF LEN(@id_card) <> 18 OR ISNUMERIC(SUBSTRING(@id_card, 1, 17)) = 0
        RETURN '无效' -- 身份证格式不正确
        
    IF CAST(SUBSTRING(@id_card, 17, 1) AS INT) % 2 = 1
        SET @gender = '男'
    ELSE
        SET @gender = '女'
        
    RETURN @gender
END

使用函数：

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SELECT id_card, dbo.GetGenderByIdCard(id_card) AS 性别
FROM users

3. 包含15位和18位身份证的判断

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SELECT 
    id_card,
    CASE 
        WHEN LEN(id_card) = 15 THEN -- 15位旧身份证
            CASE 
                WHEN CAST(SUBSTRING(id_card, 15, 1) AS INT) % 2 = 1 
                THEN '男' 
                ELSE '女' 
            END
        WHEN LEN(id_card) = 18 THEN -- 18位新身份证
            CASE 
                WHEN CAST(SUBSTRING(id_card, 17, 1) AS INT) % 2 = 1 
                THEN '男' 
                ELSE '女' 
            END
        ELSE '格式错误'
    END AS 性别
FROM users

注意事项

异常处理：在实际使用时需要确保截取的字符是数字
性能优化：如果数据量较大，可以添加索引
数据验证：应先验证身份证格式是否正确

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-- 更安全的查询（处理可能的非数字情况）
SELECT 
    id_card,
    CASE 
        WHEN ISNUMERIC(SUBSTRING(id_card, 17, 1)) = 1
        THEN CASE 
                WHEN CAST(SUBSTRING(id_card, 17, 1) AS INT) % 2 = 1 
                THEN '男' 
                ELSE '女' 
             END
        ELSE '未知'
    END AS 性别
FROM users
WHERE LEN(id_card) = 18;

提取年龄等其他信息（扩展）

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-- 提取出生日期和计算年龄
SELECT 
    id_card,
    CASE 
        WHEN LEN(id_card) = 18 
        THEN CONVERT(DATE, SUBSTRING(id_card, 7, 8))
        WHEN LEN(id_card) = 15 
        THEN CONVERT(DATE, '19' + SUBSTRING(id_card, 7, 6))
    END AS 出生日期,
    DATEDIFF(YEAR, 
        CONVERT(DATE, 
            CASE 
                WHEN LEN(id_card) = 18 
                THEN SUBSTRING(id_card, 7, 8)
                WHEN LEN(id_card) = 15 
                THEN '19' + SUBSTRING(id_card, 7, 6)
            END
        ), 
        GETDATE()
    ) AS 年龄
FROM users