/// <summary>
/// Convierte una lista de FROM a SQL.
/// Devuelve si la lista de FROMs tiene aliases
/// </summary>
/// <param name="item">Elemento que representa ya sea a un FROM o a una lista de JOINS</param>
/// <param name="toSql">Convierte una expresión a SQL</param>
/// <param name="paramSql">Alias del parámetro en SQL</param>
/// <returns></returns>
static (string sql, bool named) JoinToStrAlias(IFromListItem item, Func<Expression, string> toSql, IReadOnlyList<ExprStrRawSql> replaceMembers, string paramSql, bool forceUpperAlias, ParamMode paramMode, SqlParamDic paramDic)
{
if (item is SqlJoin join)
{
var currentAlias = toSql(join.Map.Parameters[1]);
var currentOnStr = toSql(join.On.Body);
var leftParam = join.Map.Parameters[0];
var leftAlias = ReplaceStringAliasMembers(leftParam, replaceMembers);
var rightSubsNoRep = ReplaceSubqueryLambda(join.Right, leftParam, replaceMembers);
//Visitar el lado derecho del JOIN:
//TODO: Hacer una función para visitar a las expresiones de lado derecho del JOIN
var rightSubs = SqlRewriteVisitor.VisitFromItem(rightSubsNoRep);
var rightFunc = Expression.Lambda(rightSubs).Compile();
var rightExec = (IFromListItemTarget)rightFunc.DynamicInvoke(new object[0]);
var latStr = join.Lateral ? "LATERAL " : "";
var typeStr =
join.Type == JoinType.Inner ? "" :
join.Type == JoinType.Left ? "LEFT " :
join.Type == JoinType.Right ? "RIGHT " :
join.Type == JoinType.Outter ? "OUTTER " :
join.Type == JoinType.Cross ? "CROSS " :
throw new ArgumentException("Join type " + join.Type + " invalido");
var right = $"{typeStr}JOIN {latStr}{SubqueryParenthesis(StatementStr.StatementToString(rightExec, paramMode, paramDic))} {currentAlias} ON {currentOnStr}";
var leftStr = JoinToStrAlias(join.Left, toSql, replaceMembers, leftAlias, true, paramMode, paramDic);
return (leftStr.sql + Environment.NewLine + right, true);
}
else if (item is ISqlFrom from)
{
var fromIt = StatementStr.StatementToString(from.Target, paramMode, paramDic);
return ($"FROM {SubqueryParenthesis(fromIt)} {(((fromIt is QueryToStrResult) || forceUpperAlias) ? paramSql : "")}", false);
}
else if (item is FromListAlias alias)
{
return JoinToStrAlias(alias.From, toSql, replaceMembers, paramSql, forceUpperAlias, paramMode, paramDic);
}
throw new ArgumentException("El from-item debe de ser un JOIN, FROM o Alias()");
}
/// <summary>
/// Converts an UNION clause to string
/// </summary>
static string UnionToStr(UnionClause clause, SqlExprParams pars)
{
var b = new StringBuilder();
var typeStr =
clause.Type == UnionType.Union ?
(
clause.Uniqueness == UnionUniqueness.All ?
"UNION ALL" : "UNION"
) :
clause.Type == UnionType.Intersect ? "INTERSECT" :
clause.Type == UnionType.Except ? "EXCEPT" :
throw new ArgumentException();
var queryStr = StatementStr.QueryToStr(clause.Query, pars.ParamMode, pars.ParamDic);
b.AppendLine(typeStr);
b.AppendLine("(");
b.AppendLine(TabStr(queryStr.Sql));
b.Append(")");
return(b.ToString());
}