T SQL 条件字符串连接 [英] T SQL Conditional String Concatenation

问题描述

有 5 列地址数据.我需要将这些字段连接到一个地址中，如果它们存在，则值之间有空格.如果该列有一个空值，我应该跳过它并且不输入任何空格.

Have a 5 columns of address data. I need to concatenate these fields into a single address with spaces in between the values if they exist. If the column has a null value I should skip it and not enter any space.

select 
        case 
            when street_number != '' THEN (cast(street_number as int)) 
        end as street_number,
        case
            when street_ext != '' then
                    case
                        when street_ext = 50 then '1/2'
                    end
        end as street_ext,
        case
            when street_direct ! = '' then street_direct
        end as street_direct,
        case
            when site_street ! = '' then site_street
        end as site_street,
        case
            when site_address ! = '' then site_address
        end as site_address
    from parcel 

我想做的是有一个变量并将其分配给第一列 street_number 的值，然后当我转到下一列 street_ext 时，如果它不为空，我想检查一下查看变量是否为空，如果不是，则附加一个空格和值...等等.

what I'd like to do is have a variable and assign it to the value of the first column street_number, then when I move on to the next column, street_ext, if it isn't null I'd like to check to see if the variable is null and if not, append a space and the value...and so on down the road.

我生锈了，可以朝正确的方向推动.

I'm rusty as hell and could use a push in the right direction.

谢谢大家.

推荐答案

在 TSQL 中使用+"连接字符串:

Use the "+" to concatenate strings in TSQL:

SELECT CASE 
         WHEN LEN(p.street_number) > 0 THEN p.street_number + ' ' 
         ELSE '' 
       END +
       CASE 
         WHEN p.street_ext = 50 THEN '1/2'
         WHEN LEN(p.street_ext) > 0 THEN ''
         ELSE p.street_ext
       END + ' ' +
       CASE 
         WHEN LEN(p.street_direct) > 0 THEN p.street_direct + ' '
         ELSE ''
       END + 
       CASE 
         WHEN LEN(p.site_street) > 0 THEN p.site_street + ' '
         ELSE ''
       END  + 
       CASE 
         WHEN LEN(p.site_address) > 0 THEN p.site_address + ' '
         ELSE ''
       END AS full_address
FROM PARCEL p

LEN 函数如果字符串值为 NULL，则返回零，或零长度字符串.

The LEN function returns zero if the string value is NULL, or a zero length string.

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