问下存储过程中使用case end以及字符串连接是否会影响查询效率
例如:
SELECT top 1 @gongzhi = case [jibie] when 1 then [prov]+[city]+' ' +[address]+' '+[gift] else [country]+' ' +[gift] end
FROM [kehu]
WHERE @jifen BETWEEN [begin] AND [end]
对比
SELECT top 1 @gongzhi = [gift_old]
FROM [kehu]
WHERE @jifen BETWEEN [begin] AND [end]
影响程度有多大?