/// <summary>
/// 返回时间加减的表达式1:DAY 2:HOUR 3:MINUTE 4:SECOND
/// </summary>
/// <param name="connType"></param>
/// <param name="dateType"></param>
/// <param name="Value"></param>
/// <returns></returns>
public static string GetDateAddString(this DbConnType connType, DATEPART dateType, int Value)
{
if (dateType == DATEPART.MS)
{
throw new NotSupportedException("DATEPART.MS");
}
string sym = "+";
if (0 > Value)//减
{
Value *= -1;
sym = "-";
}
string result = "";
switch (dateType)
{
case DATEPART.DAY: //天数
if (connType.IsMySQL())
{
result = $"{sym} INTERVAL {Value} DAY";
}
else if (connType == DbConnType.POSTGRESQL)
{
result = $"{sym} interval '{Value} days'";
}
else
{
result = $"{sym}{Value}";
}
break;
case DATEPART.HOUR: //小时
if (connType.IsMySQL())
{
result = $"{sym} INTERVAL {Value} HOUR";
}
else if (connType == DbConnType.POSTGRESQL)
{
result = $"{sym} interval '{Value} hours'";
}
else
{
result = $"{sym}{Value}/24.0";
}
break;
case DATEPART.MINUTE: //分时
if (connType.IsMySQL())
{
result = $"{sym} INTERVAL {Value} MINUTE";
}
else if (connType == DbConnType.POSTGRESQL)
{
result = $"{sym} interval '{Value} minutes'";
}
else
{
result = $"{sym}{Value}/1440.0";
}
break;
case DATEPART.SECOND:
if (connType.IsMySQL())
{
result = $"{sym} INTERVAL {Value} seconds";
}
else if (connType == DbConnType.POSTGRESQL)
{
result = $"{sym} interval '{Value} seconds'";
}
else
{
result = $"{sym}{Value}/86400.0";
}
break;
}
return(result);
}
public static string GetDateAddString(this DbContext connInfo, DATEPART dateType, int Value)
{
return(connInfo.DbType.GetDateAddString(dateType, Value));
}