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SqlServer Queryable.First optimization

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skx 2021-02-06 16:02:07 +08:00
parent fcbf350b63
commit df00b11d92
1 changed files with 35 additions and 0 deletions
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35
Src/Asp.Net/SqlSugar/Realization/SqlServer/SqlBuilder/SqlServerQueryBuilder.cs
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@ -15,5 +15,40 @@ namespace SqlSugar
return "SELECT {0}{"+UtilConstants.ReplaceKey+"} FROM {1}{2}{3}{4}";
}
}
public override string ToSqlString()
{
string oldOrderBy = this.OrderByValue;
string externalOrderBy = oldOrderBy;
var isIgnoreOrderBy = this.IsCount && this.PartitionByValue.IsNullOrEmpty();
AppendFilter();
sql = new StringBuilder();
if (this.OrderByValue == null && (Skip != null || Take != null)) this.OrderByValue = " ORDER BY GetDate() ";
if (this.PartitionByValue.HasValue())
{
this.OrderByValue = this.PartitionByValue + this.OrderByValue;
}
var isFirst = (Skip == 0 || Skip == null) && Take == 1;
var isRowNumber = (Skip != null || Take != null) && !isFirst;
var rowNumberString = string.Format(",ROW_NUMBER() OVER({0}) AS RowIndex ", GetOrderByString);
string groupByValue = GetGroupByString + HavingInfos;
string orderByValue = (!isRowNumber && this.OrderByValue.HasValue()) ? GetOrderByString : null;
if (isIgnoreOrderBy) { orderByValue = null; }
sql.AppendFormat(SqlTemplate, isFirst ? (" TOP 1 " + GetSelectValue) : GetSelectValue, GetTableNameString, GetWhereValueString, groupByValue, orderByValue);
sql.Replace(UtilConstants.ReplaceKey, isRowNumber ? (isIgnoreOrderBy ? null : rowNumberString) : null);
if (isIgnoreOrderBy) { this.OrderByValue = oldOrderBy; return sql.ToString(); }
var result = isFirst ? sql.ToString() : ToPageSql(sql.ToString(), this.Take, this.Skip);
if (ExternalPageIndex > 0)
{
if (externalOrderBy.IsNullOrEmpty())
{
externalOrderBy = " ORDER BY GetDate() ";
}
result = string.Format("SELECT *,ROW_NUMBER() OVER({0}) AS RowIndex2 FROM ({1}) ExternalTable ", GetExternalOrderBy(externalOrderBy), result);
result = ToPageSql2(result, ExternalPageIndex, ExternalPageSize, true);
}
this.OrderByValue = oldOrderBy;
return result;
}
}
}