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in Technique[技术] by (71.8m points)

sql查询问题 返回结果集或者参数

问题描述:
sql查询,如果结果集不为空则返回结果集。如果结果集为空,则返回查询参数?

说明如下:

SELECT CASE 
        WHEN a IS NULL THEN '${k}'
        ELSE a
    END AS a;

(SELECT a
FROM A

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by (71.8m points)

为什么要用数据库承担这些,你这个在代码逻辑里面实现才是正道


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
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