Conditional Expression Functions describes the examples. openGauss=# SELECT DECODE('A','A',1,'B',2,0); case --- 1 (1 row) COALESCE Figure 3 shows the syntax of a COALESCE expression. Figure 3 coalesce::= COALESCE returns its first not-NULL value. If all the parameters are NULL,...
{"version":"2017-02-28","operation":"PutItem","key":{"id":{"S":"1"} },"condition":{"expression":"attribute_not_exists(id)"} } By default, if the condition check fails, the AWS AppSync DynamoDB resolver returns an error for the mutation. However, the AWS AppSync Dynamo...
Condition(Expression, Expression, Expression) 创建一个表示条件语句的ConditionalExpression。 Condition(Expression, Expression, Expression, Type) 创建一个表示条件语句的ConditionalExpression。 Condition(Expression, Expression, Expression) Source: ConditionalExpression.cs ...
The expression attribute value :v_sub is a placeholder for 20. size (Brand) <= :v_sub If the attribute is of type Binary, size returns the number of bytes in the attribute value. Example: Suppose that the ProductCatalog item has a binary attribute named VideoClip that contains a sho...
public static Condition parse(String field, Object expression) 解析为Condition Parameters: field - 字段名 expression - 表达式或普通值 Returns: Condition getField public String getField() Returns: 字段 setField public void setField(String field) 设置字段名 Parameters: field - 字段名 getOperator publi...
public RuleExpressionCondition(string conditionName); Parameters conditionName String The name of the condition to evaluate. Exceptions ArgumentNullException conditionName is a null reference (Nothing in Visual Basic). Applies to .NET Framework 4.8.1 和其他版本 产品版本 .NET Framework 3.0, 3.5,...
An expression that returns TRUE, FALSE, or UNKNOWN. For more information, see Predicates. expression Specifies a column name, a constant, a function, a variable, a scalar subquery, or any combination of column names, constants, and functions connected by an operator or operators, or a subquery...
When the condition expression is false, the thread blocks on the condition variable. The condition variable is then signaled by another thread when it changes the condition value. This causes one or all of the threads waiting on the condition to unblock and to try to acquire the mutex lock ...
Index Condition Pushdown (ICP) is an optimization for the case where MySQL retrieves rows from a table using an index. Without ICP, the storage engine traverses the index to locate rows in the base table and returns them to the MySQL server which evaluates theWHEREcondition for the rows. ...
expression A character expression such as a column or field. pattern A character expression that contains pattern matching. The wildcards that you can choose from are: WildcardExplanation %Allows you to match any string of any length (including zero length) ...