SELECT子句是用户指定要返回到查询结果表中的属性(列)的地方。用户可基于所查询表的属性,在SELECT列表中建立表达式。 SELECT子句是在FROM、WHERE、GROUP BY和HAVING子句之后处理的,这意味着SELECT子句中分配给表达式的别名,不会存在于之前的SELECT相关子句中。 例如以下语句是错误的 SELECT orderid, YEAR(orderdate) AS...
T-SQL MERGE with UPDATE SET CASE语句-没有ELSE会发生什么? 、、 我正在编写一条TSQL MERGE语句来处理UPDATE和INSERT的常见组合。我有几个select列,只有当(例如)一个参数设置为TRUE时才应该更新它们。例如: CASE END, CASE WHEN @someParameter = 1 THEN SOURCE 浏览0提问于2014-03-12得票数 3 3回答 尝...
FOR select_statement [ FOR { READ ONLY | UPDATE [ OF column_name [ , …n ] ] } ] 其中: cursor_name:所定义游标名称。 SCROLL:指定所有的提取选项(FIRST、LAST、PRIOR、NEXT、RELATIVE、ABSOLUTE)均可用。如果未指定 SCROLL,默认 NEXT。 lselect_statement:是定义游标结果集的标准 SELECT 语句。 UPDATE...
There are times where you need to write a single TSQL statement that is able to return different TSQL expressions based on the evaluation of another expression. When you need this kind of functionality you can use the CASE expression or IIF function to meet this requirement. In this article I...
EGIN和END语句用于下列情况: WHILE 循环需要包含语句块。 CASE 函数的元素需要包含语句块。 IF 或 ELSE 子句需要包含语句块。 语法: BEGIN { sql_statement |statement_block } END 参数:{ sql_statement | statement_block }使用语句块定义的任何有效的Transact-SQL ...
1.Select case statement 2.Case when and else 3.CASE: return a specified value based on a set of business logic 4.Use CASE in the UPDATE statement 5.'Case when' statement in a procedure 6.Case when NULL 7.Case when with Mod and ABS() ...
And the INSERT INTO statement syntax that is used to insert multiple rows from a source database table is like: INSERT INTO table (column1, column2, … ) SELECT expression1, expression2, … FROM source_tables [WHERE conditions]; From the previous syntax statements: The table is the...
CASE IMMEDIATE SECOND CAST IN SECTION CATALOG INCLUDE SELECT CHAR INDEX SESSION CHAR_LENGTH INDICATOR SESSION_USER CHARACTER INITIALLY SET CHARACTER_LENGTH INNER SIZE CHECK INPUT SMALLINT CLOSE INSENSITIVE SOME COALESCE INSERT SPACE COLLATE INT SQL COLLATION INTEGER SQLCA COLUMN INTERSECT...
Any data already in the table must have unique values in the primary key column or columns.If there are any duplicates, the ALTER TABLE statement will fail. 在数据表中的任何数据必须在主键表中有唯一的值。如果有任何重复的,ALTER TABLE语句将失败。
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