[英]Substitution inside verbatim string literals?
與此相關的問題 。有關如何內C#寫長長的SQL查詢,該解決方案建議,長的SQL查詢應該寫成:
string query = @"
SELECT
c.CUSTOMER_ID,
COALESCE (c.FIRST_NAME, ''_ + ' ' + COALESCE (c.LAST_NAME, '') AS FULL_NAME
ct.NAME as CUSTOMER_TYPE
FROM
CT_CUSTOMER_TYPE AS ct INNER JOIN CUSTOMER AS c
ON ct.CUSTOMER_TYPE_ID = c.CUSTOMER_TYPE_ID
";
這讓我對另一個相關問題感到好奇。 我能以某種方式使用替代嗎? 也就是說,如果說表名更改但查詢保持不變,我將如何管理? 我是否必須回歸使用另一種使用字符串連接構建字符串的方法,還是有更優雅的方法?
為什么不使用string.Format? 在您給出的具體示例中,您可以執行類似的操作
string query = @"
SELECT
c.CUSTOMER_ID,
COALESCE (c.FIRST_NAME, ''_ + ' ' + COALESCE (c.LAST_NAME, '') AS FULL_NAME
ct.NAME as CUSTOMER_TYPE
FROM
{0} AS ct INNER JOIN {1} AS c
ON ct.CUSTOMER_TYPE_ID = c.CUSTOMER_TYPE_ID
";
並調用
string real_query = string.Format(query, tblName1, tblName2);
是的,您可以使用String.Format方法。
string custtype = "CT_CUSTOMER_TYPE";
string cust = "CUSTOMER";
string query = @"
SELECT
c.CUSTOMER_ID,
COALESCE (c.FIRST_NAME, ''_ + ' ' + COALESCE (c.LAST_NAME, '') AS FULL_NAME
ct.NAME as CUSTOMER_TYPE
FROM
{0} AS ct INNER JOIN {1} AS c
ON ct.CUSTOMER_TYPE_ID = c.CUSTOMER_TYPE_ID
";
string endQuery = String.Format(query, custtype, cust);
String.Format方法將使用字符串后面的參數順序替換{x}標識的參數,因此{0}將替換為custtype的值,而{1}將替換為cust的值。
您可以考慮使用LINQ to SQL,如果您還沒有。
回答實際問題,你可以像其他人提到的那樣使用string.Format
創建查詢。 如果要修改現有的字符串,請嘗試使用string.Replace
或Regex.Replace
描述這里 。 那是:
string query = @"
SELECT
c.CUSTOMER_ID,
COALESCE (c.FIRST_NAME, ''_ + ' ' + COALESCE (c.LAST_NAME, '') AS FULL_NAME
ct.NAME as CUSTOMER_TYPE
FROM
CT_CUSTOMER_TYPE AS ct INNER JOIN CUSTOMER AS c
ON ct.CUSTOMER_TYPE_ID = c.CUSTOMER_TYPE_ID
";
query.Replace("CT_CUSTOMER_TYPE", "NEW_TABLE_NAME");
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