Examples with NullIfExpression com.facebook.presto.sql.tree.NullIfExpression used on opensource projects

Example 1 with NullIfExpression

use of com.facebook.presto.sql.tree.NullIfExpression in project presto by prestodb.

the class AstBuilder method visitFunctionCall.

@Override
public Node visitFunctionCall(SqlBaseParser.FunctionCallContext context) {
    Optional<Expression> filter = visitIfPresent(context.filter(), Expression.class);
    Optional<Window> window = visitIfPresent(context.over(), Window.class);
    Optional<OrderBy> orderBy = Optional.empty();
    if (context.ORDER() != null) {
        orderBy = Optional.of(new OrderBy(visit(context.sortItem(), SortItem.class)));
    }
    QualifiedName name = getQualifiedName(context.qualifiedName());
    boolean distinct = isDistinct(context.setQuantifier());
    boolean ignoreNulls = context.nullTreatment() != null && context.nullTreatment().IGNORE() != null;
    if (name.toString().equalsIgnoreCase("if")) {
        check(context.expression().size() == 2 || context.expression().size() == 3, "Invalid number of arguments for 'if' function", context);
        check(!window.isPresent(), "OVER clause not valid for 'if' function", context);
        check(!distinct, "DISTINCT not valid for 'if' function", context);
        check(!filter.isPresent(), "FILTER not valid for 'if' function", context);
        Expression elseExpression = null;
        if (context.expression().size() == 3) {
            elseExpression = (Expression) visit(context.expression(2));
        }
        return new IfExpression(getLocation(context), (Expression) visit(context.expression(0)), (Expression) visit(context.expression(1)), elseExpression);
    }
    if (name.toString().equalsIgnoreCase("nullif")) {
        check(context.expression().size() == 2, "Invalid number of arguments for 'nullif' function", context);
        check(!window.isPresent(), "OVER clause not valid for 'nullif' function", context);
        check(!distinct, "DISTINCT not valid for 'nullif' function", context);
        check(!filter.isPresent(), "FILTER not valid for 'nullif' function", context);
        return new NullIfExpression(getLocation(context), (Expression) visit(context.expression(0)), (Expression) visit(context.expression(1)));
    }
    if (name.toString().equalsIgnoreCase("coalesce")) {
        check(context.expression().size() >= 2, "The 'coalesce' function must have at least two arguments", context);
        check(!window.isPresent(), "OVER clause not valid for 'coalesce' function", context);
        check(!distinct, "DISTINCT not valid for 'coalesce' function", context);
        check(!filter.isPresent(), "FILTER not valid for 'coalesce' function", context);
        return new CoalesceExpression(getLocation(context), visit(context.expression(), Expression.class));
    }
    if (name.toString().equalsIgnoreCase("try")) {
        check(context.expression().size() == 1, "The 'try' function must have exactly one argument", context);
        check(!window.isPresent(), "OVER clause not valid for 'try' function", context);
        check(!distinct, "DISTINCT not valid for 'try' function", context);
        check(!filter.isPresent(), "FILTER not valid for 'try' function", context);
        return new TryExpression(getLocation(context), (Expression) visit(getOnlyElement(context.expression())));
    }
    if (name.toString().equalsIgnoreCase("$internal$bind")) {
        check(context.expression().size() >= 1, "The '$internal$bind' function must have at least one arguments", context);
        check(!window.isPresent(), "OVER clause not valid for '$internal$bind' function", context);
        check(!distinct, "DISTINCT not valid for '$internal$bind' function", context);
        check(!filter.isPresent(), "FILTER not valid for '$internal$bind' function", context);
        int numValues = context.expression().size() - 1;
        List<Expression> arguments = context.expression().stream().map(this::visit).map(Expression.class::cast).collect(toImmutableList());
        return new BindExpression(getLocation(context), arguments.subList(0, numValues), arguments.get(numValues));
    }
    return new FunctionCall(getLocation(context), getQualifiedName(context.qualifiedName()), window, filter, orderBy, distinct, ignoreNulls, visit(context.expression(), Expression.class));
}

Example 2 with NullIfExpression

use of com.facebook.presto.sql.tree.NullIfExpression in project presto by prestodb.

the class TestSqlParser method testNullIf.

@Test
public void testNullIf() {
    assertExpression("nullif(42, 87)", new NullIfExpression(new LongLiteral("42"), new LongLiteral("87")));
    assertExpression("nullif(42, null)", new NullIfExpression(new LongLiteral("42"), new NullLiteral()));
    assertExpression("nullif(null, null)", new NullIfExpression(new NullLiteral(), new NullLiteral()));
    assertInvalidExpression("nullif(1)", "Invalid number of arguments for 'nullif' function");
    assertInvalidExpression("nullif(1, 2, 3)", "Invalid number of arguments for 'nullif' function");
    assertInvalidExpression("nullif(42, 87) filter (where true)", "FILTER not valid for 'nullif' function");
    assertInvalidExpression("nullif(42, 87) OVER ()", "OVER clause not valid for 'nullif' function");
}

Example 3 with NullIfExpression

use of com.facebook.presto.sql.tree.NullIfExpression in project presto by prestodb.

the class TestEqualityInference method testExpressionsThatMayReturnNullOnNonNullInput.

@Test
public void testExpressionsThatMayReturnNullOnNonNullInput() throws Exception {
    List<Expression> candidates = ImmutableList.of(// try_cast
    new Cast(nameReference("b"), "BIGINT", true), new FunctionCall(QualifiedName.of("try"), ImmutableList.of(nameReference("b"))), new NullIfExpression(nameReference("b"), number(1)), new IfExpression(nameReference("b"), number(1), new NullLiteral()), new DereferenceExpression(nameReference("b"), "x"), new InPredicate(nameReference("b"), new InListExpression(ImmutableList.of(new NullLiteral()))), new SearchedCaseExpression(ImmutableList.of(new WhenClause(new IsNotNullPredicate(nameReference("b")), new NullLiteral())), Optional.empty()), new SimpleCaseExpression(nameReference("b"), ImmutableList.of(new WhenClause(number(1), new NullLiteral())), Optional.empty()), new SubscriptExpression(new ArrayConstructor(ImmutableList.of(new NullLiteral())), nameReference("b")));
    for (Expression candidate : candidates) {
        EqualityInference.Builder builder = new EqualityInference.Builder();
        builder.extractInferenceCandidates(equals(nameReference("b"), nameReference("x")));
        builder.extractInferenceCandidates(equals(nameReference("a"), candidate));
        EqualityInference inference = builder.build();
        List<Expression> equalities = inference.generateEqualitiesPartitionedBy(matchesSymbols("b")).getScopeStraddlingEqualities();
        assertEquals(equalities.size(), 1);
        assertTrue(equalities.get(0).equals(equals(nameReference("x"), nameReference("b"))) || equalities.get(0).equals(equals(nameReference("b"), nameReference("x"))));
    }
}