sqlsugar/Src/OracleUS7ASCII/SqlSugar/ExpressionsToSql/Subquery/Items/SubDistinctCount.cs

82 lines
2.3 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
namespace SqlSugar
{
public class SubDistinctCount : ISubOperation
{
public bool HasWhere
{
get; set;
}
public string Name
{
get
{
return "DistinctCount";
}
}
public Expression Expression
{
get; set;
}
public int Sort
{
get
{
return 200;
}
}
public ExpressionContext Context
{
get; set;
}
public string GetValue(Expression expression = null)
{
var exp = expression as MethodCallExpression;
var argExp = exp.Arguments[0];
InitType(exp);
var parametres = (argExp as LambdaExpression).Parameters;
if ((argExp as LambdaExpression).Body is UnaryExpression)
{
argExp = ((argExp as LambdaExpression).Body as UnaryExpression).Operand;
}
var argLambda = argExp as LambdaExpression;
if (this.Context.InitMappingInfo != null && argLambda != null && argLambda.Parameters.Count > 0)
{
foreach (var item in argLambda.Parameters)
{
this.Context.InitMappingInfo(item.Type);
}
this.Context.RefreshMapping();
}
var result = "COUNT(DISTINCT " + SubTools.GetMethodValue(Context, argExp, ResolveExpressType.WhereMultiple) + ")";
var selfParameterName = Context.GetTranslationColumnName(parametres.First().Name) + UtilConstants.Dot;
if (this.Context.JoinIndex == 0)
result = result.Replace(selfParameterName, SubTools.GetSubReplace(this.Context));
return result;
}
private void InitType(MethodCallExpression exp)
{
foreach (var arg in (exp.Arguments[0] as LambdaExpression).Parameters)
{
if (this.Context.InitMappingInfo != null)
{
this.Context.InitMappingInfo(arg.Type);
this.Context.RefreshMapping();
}
}
}
}
}