Examples with DECIMAL org.apache.flink.table.types.logical.LogicalTypeRoot.DECIMAL used on opensource projects

Example 1 with DECIMAL

use of org.apache.flink.table.types.logical.LogicalTypeRoot.DECIMAL in project flink by apache.

the class LogicalTypeMerging method findCommonType.

/**
 * Returns the most common, more general {@link LogicalType} for a given set of types. If such a
 * type exists, all given types can be casted to this more general type.
 *
 * <p>For example: {@code [INT, BIGINT, DECIMAL(2, 2)]} would lead to {@code DECIMAL(21, 2)}.
 *
 * <p>This class aims to be compatible with the SQL standard. It is inspired by Apache Calcite's
 * {@code SqlTypeFactoryImpl#leastRestrictive} method.
 */
public static Optional<LogicalType> findCommonType(List<LogicalType> types) {
    Preconditions.checkArgument(types.size() > 0, "List of types must not be empty.");
    // collect statistics first
    boolean hasRawType = false;
    boolean hasNullType = false;
    boolean hasNullableTypes = false;
    for (LogicalType type : types) {
        final LogicalTypeRoot typeRoot = type.getTypeRoot();
        if (typeRoot == RAW) {
            hasRawType = true;
        } else if (typeRoot == NULL) {
            hasNullType = true;
        }
        if (type.isNullable()) {
            hasNullableTypes = true;
        }
    }
    final List<LogicalType> normalizedTypes = types.stream().map(t -> t.copy(true)).collect(Collectors.toList());
    LogicalType foundType = findCommonNullableType(normalizedTypes, hasRawType, hasNullType);
    if (foundType == null) {
        foundType = findCommonCastableType(normalizedTypes);
    }
    if (foundType != null) {
        final LogicalType typeWithNullability = foundType.copy(hasNullableTypes);
        // NULL is reserved for untyped literals only
        if (typeWithNullability.is(NULL)) {
            return Optional.empty();
        }
        return Optional.of(typeWithNullability);
    }
    return Optional.empty();
}