private void VisitCorrelationStatement(CorrelationStatement statement, string functionName)
{
SelectStatement statement1 = (SelectStatement)statement.First;
SelectStatement statement2 = (SelectStatement)statement.Second;
if (((statement1.From.Count != 1) && (!(statement1.From[0].Source is Name))) ||
((statement2.From.Count != 1) && (!(statement2.From[0].Source is Name))))
{
throw new NotImplementedException();
}
else if ((statement1.Output.Count != statement2.Output.Count) && (statement1.Output.Count == 0))
{
throw new NotImplementedException();
}
string table1 = ((Name)(statement1.From[0].Source)).LastPart;
string table2 = ((Name)(statement2.From[0].Source)).LastPart;
ExpressionToken whereExpression = null;
List <ExpressionToken> expressions1 = new List <ExpressionToken>();
List <ExpressionToken> expressions2 = new List <ExpressionToken>();
for (int i = 0; i < statement1.Output.Count; i++)
{
if ((!(statement1.Output[i] is Name)) && (!(statement2.Output[i] is Name)))
{
throw new NotImplementedException();
}
expressions1.Add(Sql.Name(table1, ((Name)(statement1.Output[i])).LastPart));
expressions2.Add(Sql.Name(table2, ((Name)(statement2.Output[i])).LastPart));
if (whereExpression == null)
{
whereExpression = expressions1[i].IsEqual(expressions2[i]);
}
else
{
whereExpression = whereExpression.And(expressions1[i].IsEqual(expressions2[i]));
}
}
if (statement2.Where != null)
{
whereExpression = whereExpression.And(AddPrefixToExpressionToken(((ExpressionToken)statement2.Where), table2));
}
ExpressionToken tempExpression = Sql.Function(functionName, Sql.Select.From(table2).Where(whereExpression));
if (statement1.Where != null)
{
tempExpression = tempExpression.And(AddPrefixToExpressionToken(((ExpressionToken)statement1.Where), table1));
}
SelectStatement correlationStatement =
Sql.Select.Output(expressions1).From(table1)
.Where(tempExpression);
VisitStatement(correlationStatement);
}
private void VisitCorrelationStatement(CorrelationStatement statement, string functionName)
{
SelectStatement statement1 = (SelectStatement)statement.First;
SelectStatement statement2 = (SelectStatement)statement.Second;
if (((statement1.From.Count != 1) && (!(statement1.From[0].Source is Name))) ||
((statement2.From.Count != 1) && (!(statement2.From[0].Source is Name))))
{
throw new NotImplementedException();
}
else if ((statement1.Output.Count != statement2.Output.Count) && (statement1.Output.Count == 0))
{
throw new NotImplementedException();
}
string table1 = ((Name)(statement1.From[0].Source)).LastPart;
string table2 = ((Name)(statement2.From[0].Source)).LastPart;
var table1Name = ((Name)(statement1.From[0].Source));
var table2Name = ((Name)(statement2.From[0].Source));
var statement1Alias = statement1.Alias;
//here we have 2 possible cases
//case 1) table1Name equals table2Name
// In this case "EXIST" statement will not work properly.To fix that, first statement, including it's own "WHERE" expression
//should be placed inside subquery with alias
//case 2) table1Name not equal table2Name
// in this case it is not nessesary to use subquery for first statement. Just place WHERE clause to EXIST part
var isSameTableMode = string.Equals($"{table1Name.FirstPart}.{table1Name.LastPart}"
, $"{table2Name.FirstPart}.{table2Name.LastPart}"
, StringComparison.OrdinalIgnoreCase);
ExpressionToken whereExpression = null;
List <ExpressionToken> expressions1 = new List <ExpressionToken>();
List <ExpressionToken> expressions2 = new List <ExpressionToken>();
for (int i = 0; i < statement1.Output.Count; i++)
{
if ((!(statement1.Output[i] is Name)) && (!(statement2.Output[i] is Name)))
{
throw new NotImplementedException();
}
Name name1 = null;
if (isSameTableMode)
{
// use alias of first statements since we will use subquery for it
name1 = Sql.Name(statement1Alias, ((Name)(statement1.Output[i])).Alias).As(((Name)(statement1.Output[i])).Alias);
}
else
{
//use table name or alias directly
if (!string.IsNullOrWhiteSpace(table1Name.Alias))
{
name1 = Sql.Name(table1Name.Alias, ((Name)(statement1.Output[i])).LastPart).As(((Name)(statement1.Output[i])).Alias);
}
else
{
name1 = Sql.Name(table1Name.FirstPart, table1Name.LastPart, ((Name)(statement1.Output[i])).LastPart).As(((Name)(statement1.Output[i])).Alias);
}
}
expressions1.Add(name1);
if (!string.IsNullOrWhiteSpace(table2Name.Alias))
{
expressions2.Add(Sql.Name(table2Name.Alias, ((Name)(statement2.Output[i])).LastPart).As(((Name)(statement2.Output[i])).Alias));
}
else
{
expressions2.Add(Sql.Name(table2Name.FirstPart, table2Name.LastPart, ((Name)(statement2.Output[i])).LastPart).As(((Name)(statement2.Output[i])).Alias));
}
if (whereExpression == null)
{
whereExpression = expressions1[i].IsEqual(expressions2[i]);
}
else
{
whereExpression = whereExpression.And(expressions1[i].IsEqual(expressions2[i]));
}
}
if (statement2.Where != null)
{
whereExpression = whereExpression.And(AddPrefixToExpressionToken(((ExpressionToken)statement2.Where), table2Name.LastPart));
}
ExpressionToken tempExpression = Sql.Function(functionName, Sql.Select.From(table2Name).Where(whereExpression));
if (statement1.Where != null && !isSameTableMode)
{
tempExpression = tempExpression.And(AddPrefixToExpressionToken(((ExpressionToken)statement1.Where), table1Name.LastPart));
}
SelectStatement correlationStatement = null;
correlationStatement = isSameTableMode
? Sql.Select.Output(expressions1) //case 1
.From(statement1)
.Where(tempExpression)
: Sql.Select.Output(expressions1) //case 2
.From(table1Name)
.Where(tempExpression);
VisitStatement(correlationStatement);
}