TSQL是一种用于管理和操作关系型数据库的编程语言,它支持使用CASE语句来更新多个列,但更新操作的结果取决于特定的值。 CASE语句是一种条件表达式,它允许根据不同的条件执行不同的操作。在TSQL中,可以使用CASE语句来更新多个列的值,具体步骤如下: 使用UPDATE语句来指定要更新的表和列。
Because we defined the Staff column in the subquery, we can refer to it in the outer query. This makes re-using code much easier and it makes the SQL statement more compact and easier to maintain. If we would like to change the definition of Staff, we would need to alter it at only...
We have following output of this query. In this output, we get minimum and maximum salary for a particular designation. Update statement with a CASE statement We can use a Case statement in SQL with update DML as well. Suppose we want to update Statecode of employees based on Case statem...
from student); [Err] 1093 - You can't specify target table 'student' for update in FROM clause 描述: 如果子查询的...解决方法: 通过给 from 子句中的结果集起别名。...student m where m.id = 1; [Err] 1064 - You have an error in your SQL syntax; 描述: delete from table 这样的句子...
, IN v_str varchar(30) ) BEGIN CASE n_str WHEN n_str = 'profileStatus' THEN UPDATE tbl_contact SET status = 'A' WHERE id = id; -- The above statement updates the entire table instead of the right row WHEN n_str = 'phoneNumberMobile' THEN ...
And that is how SQL Case statement is used in an Order by clause: Here’s another example with the SQL Where Case. This might not be a good SQL Where Case statement because the query below does not make any sense, right? 1 2 3 SELECT * FROM Production.Product p WHERE 1 = ...
'VARCHAR' is not a recognized built-in function name. 'WHEN MATCHED' cannot appear more than once in a 'UPDATE' clause of a MERGE statement. "EXECUTE AT" with Dynamic Linked Server Name "explicit value must be specified for identity column in table" error in SQL 2000 "FROM clause have ...
CASE can be used in any statement or clause that allows a valid expression. For example, you can use CASE in statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as , IN, WHERE, ORDER BY, and HAVING.Transact-SQL syntax...
The SQL CASE Expression TheCASEexpression goes through conditions and returns a value when the first condition is met (like an if-then-else statement). So, once a condition is true, it will stop reading and return the result. If no conditions are true, it returns the value in theELSE...
, IN v_str varchar(30) ) BEGIN CASE n_str WHEN n_str = 'profileStatus' THEN UPDATE tbl_contact SET status = 'A' WHERE id = id; -- The above statement updates the entire table instead of the right row WHEN n_str = 'phoneNumberMobile' THEN ...