本文整理汇总了Golang中github.com/pingcap/tidb/expression.AggregationFunction.IsDistinct方法的典型用法代码示例。如果您正苦于以下问题：Golang AggregationFunction.IsDistinct方法的具体用法？Golang AggregationFunction.IsDistinct怎么用？Golang AggregationFunction.IsDistinct使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类github.com/pingcap/tidb/expression.AggregationFunction的用法示例。
在下文中一共展示了AggregationFunction.IsDistinct方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Golang代码示例。
示例1: isDecomposable
// isDecomposable checks if an aggregate function is decomposable. An aggregation function $F$ is decomposable
// if there exist aggregation functions F_1 and F_2 such that F(S_1 union all S_2) = F_2(F_1(S_1),F_1(S_2)),
// where S_1 and S_2 are two sets of values. We call S_1 and S_2 partial groups.
// It's easy to see that max, min, first row is decomposable, no matter whether it's distinct, but sum(distinct) and
// count(distinct) is not.
// Currently we don't support avg and concat.
func (a *aggPushDownSolver) isDecomposable(fun expression.AggregationFunction) bool {
switch fun.GetName() {
case ast.AggFuncAvg, ast.AggFuncGroupConcat:
// TODO: Support avg push down.
return false
case ast.AggFuncMax, ast.AggFuncMin, ast.AggFuncFirstRow:
return true
case ast.AggFuncSum, ast.AggFuncCount:
return !fun.IsDistinct()
default:
return false
}
}