SQL Server allows for only 10 levels of nesting inCASEexpressions. TheCASEexpression can't be used to control the flow of execution of Transact-SQL statements, statement blocks, user-defined functions, and stored procedures. For a list of control-of-flow methods, seeControl-of-Flow Language (...
Lets you conditionally return specific values from multiple comparisons. There are two types of case statements: A simple case statement that compares an expression to a set of simple expressions to return spec
...In this case, we have two SQL IF statements...我们可以在SQL IF语句中使用BEGIN和END语句块。 一旦满足条件,它将在相应的BEGIN和End块内执行代码。...我们也可以使用SQL IF语句和BEGIN END块指定多个语句。 在下面的查询中,我们希望在满足条件后从两个打印语句中打印一条消息。...在本文中,我们通过示...
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 select_list, IN, WHERE, ORDER BY, and HAVING. --Syntax for SQL Server and Azure SQL DatabaseSimple...
CASE selector WHEN selector_value_1 THEN statements_1 WHEN selector_value_1 THEN statement_2 ... ELSE else_statements END CASE;Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) Let’s examine the syntax of the simple CASE statement in detail: 1) selector The selector is an ...
3. Types of CASE Statements There are two main types of CASE statements in SQL: simple CASE searched CASE They differ in how they compare values or evaluate conditions. 3.1. Simple CASE To begin with,a simple CASE statement compares an expression to one or more possible values. It has a ...
论SQL Server数据库中Case函数的作用
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 select_list, IN, WHERE, ORDER BY, and HAVING. ...
supportsOpenStatementsAcrossRollback 方法 (SQLServerDatabaseMetaData) supportsOrderByUnrelated 方法 (SQLServerDatabaseMetaData) supportsOuterJoins 方法 (SQLServerDatabaseMetaData) supportsPositionedDelete 方法(SQLServerDatabaseMetaData) supportsPositionedUpdate 方法(SQLServerDatabaseMetaData) supports...
(默认限制为10条,performance_schema_events_statements_history_size ): UPDATE performance_schema.setup_consumers...'events_statements_history_long' OR name LIKE 'events_transactions_history_long'; 现在激活了计量,我们可以使用以下语句查看所有新事务的历史记录...,我们可以查询在这个长事务中已经执行...