Cast.java
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// to you under the Apache License, Version 2.0 (the
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//
// http://www.apache.org/licenses/LICENSE-2.0
//
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package org.apache.doris.nereids.trees.expressions;
import org.apache.doris.nereids.exceptions.UnboundException;
import org.apache.doris.nereids.trees.expressions.functions.Monotonic;
import org.apache.doris.nereids.trees.expressions.literal.Literal;
import org.apache.doris.nereids.trees.expressions.shape.UnaryExpression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.DataType;
import org.apache.doris.nereids.types.DecimalV2Type;
import org.apache.doris.nereids.types.DecimalV3Type;
import org.apache.doris.nereids.types.coercion.DateLikeType;
import org.apache.doris.qe.ConnectContext;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.Objects;
/**
* cast function.
*/
public class Cast extends Expression implements UnaryExpression, Monotonic {
// CAST can be from SQL Query or Type Coercion.
private final boolean isExplicitType;
private final DataType targetType;
public Cast(Expression child, DataType targetType, boolean isExplicitType) {
super(ImmutableList.of(child));
this.targetType = Objects.requireNonNull(targetType, "targetType can not be null");
this.isExplicitType = isExplicitType;
}
public Cast(Expression child, DataType targetType) {
super(ImmutableList.of(child));
this.targetType = Objects.requireNonNull(targetType, "targetType can not be null");
this.isExplicitType = false;
}
private Cast(List<Expression> child, DataType targetType, boolean isExplicitType) {
super(child);
this.targetType = Objects.requireNonNull(targetType, "targetType can not be null");
this.isExplicitType = isExplicitType;
}
public boolean isExplicitType() {
return isExplicitType;
}
@Override
public DataType getDataType() {
return targetType;
}
@Override
public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
return visitor.visitCast(this, context);
}
@Override
public boolean nullable() {
if (ConnectContext.get().getSessionVariable().enableStrictCast()) {
if (targetType.isNumericType() || targetType.isDateLikeType() || targetType.isBooleanType()) {
return child().nullable();
}
DataType childDataType = child().getDataType();
if (childDataType.isStringLikeType() && !targetType.isStringLikeType()) {
return true;
} else if (!childDataType.isDateLikeType() && targetType.isDateLikeType()) {
return true;
} else if (!childDataType.isTimeType() && targetType.isTimeType()) {
return true;
} else if (childDataType.isJsonType() || targetType.isJsonType()) {
return true;
} else if (childDataType.isVariantType() || targetType.isVariantType()) {
return true;
} else {
return child().nullable();
}
} else {
return unStrictCastNullable();
}
}
protected boolean unStrictCastNullable() {
if (child().nullable()) {
return true;
}
DataType childDataType = child().getDataType();
if (childDataType.isStringLikeType() && !targetType.isStringLikeType()) {
return true;
} else if (targetType.isDateLikeType() || targetType.isTimeType()) {
// for date/time types, parsing or converting from numbers may generate null.
// datetime scale reduction may also generate null. that's all for them.
if (childDataType.isStringLikeType() || childDataType.isNumericType()) {
return true;
} else if (childDataType.isDateTimeV2Type() && targetType.isDateTimeV2Type()) {
return true;
} else if (childDataType.isTimeType() && targetType.isTimeType()) {
return true;
}
return false;
} else if (childDataType.isJsonType() || targetType.isJsonType()) {
return true;
} else if (childDataType.isVariantType() || targetType.isVariantType()) {
return true;
} else if (childDataType.isIntegralType()) {
// integral to integral
if (targetType.isIntegralType()) {
if (childDataType.isLargeIntType() && !targetType.isLargeIntType()) {
return true;
}
if (childDataType.isBigIntType() && !targetType.isLargeIntType() && !targetType.isBigIntType()) {
return true;
}
if (childDataType.isIntegerType() && (targetType.isSmallIntType() || targetType.isTinyIntType())) {
return true;
}
return childDataType.isSmallIntType() && targetType.isTinyIntType();
} else if (targetType.isDecimalLikeType()) {
// Integral to decimal
int range = targetType.isDecimalV2Type() ? ((DecimalV2Type) targetType).getRange()
: ((DecimalV3Type) targetType).getRange();
if (childDataType.isTinyIntType() && range < 3) {
return true;
} else if (childDataType.isTinyIntType() && range < 3) {
return true;
} else if (childDataType.isSmallIntType() && range < 5) {
return true;
} else if (childDataType.isIntegerType() && range < 10) {
return true;
} else if (childDataType.isBigIntType() && range < 19) {
return true;
} else {
return childDataType.isLargeIntType() && range < 39;
}
}
} else if (childDataType.isFloatType() || childDataType.isDoubleType()) {
// Double/Float to integral or decimal
return targetType.isIntegralType() || targetType.isDecimalLikeType();
} else if (childDataType.isDecimalLikeType()) {
// Decimal to integral
if (targetType.isIntegralType()) {
int range = 0;
if (childDataType.isDecimalV2Type()) {
range = ((DecimalV2Type) childDataType).getRange();
} else {
range = ((DecimalV3Type) childDataType).getRange();
}
if (range >= 39) {
return true;
}
if (targetType.isTinyIntType() && range >= 3) {
return true;
}
if (targetType.isSmallIntType() && range >= 5) {
return true;
}
if (targetType.isIntegerType() && range >= 10) {
return true;
}
return targetType.isBigIntType() && range >= 19;
} else if (targetType.isDecimalLikeType()) {
// Decimal to decimal
int targetRange = targetType.isDecimalV2Type() ? ((DecimalV2Type) targetType).getRange()
: ((DecimalV3Type) targetType).getRange();
int sourceRange = childDataType.isDecimalV2Type() ? ((DecimalV2Type) childDataType).getRange()
: ((DecimalV3Type) childDataType).getRange();
return sourceRange > targetRange;
}
} else if (childDataType.isTimeType() && targetType.isIntegralType()) {
// Time to integral
return targetType.isTinyIntType() || targetType.isSmallIntType() || targetType.isIntegerType();
} else if (childDataType.isBooleanType() && targetType.isDecimalLikeType()) {
// Boolean to decimal
return (targetType.isDecimalV2Type() ? ((DecimalV2Type) targetType).getRange()
: ((DecimalV3Type) targetType).getRange()) <= 1;
}
return false;
}
@Override
public Cast withChildren(List<Expression> children) {
Preconditions.checkArgument(children.size() == 1);
return new Cast(children, targetType, isExplicitType);
}
@Override
public String computeToSql() throws UnboundException {
return "cast(" + child().toSql() + " as " + targetType.toSql() + ")";
}
@Override
public String toString() {
return "cast(" + child() + " as " + targetType + ")";
}
@Override
public boolean equals(Object o) {
if (!super.equals(o)) {
return false;
}
Cast cast = (Cast) o;
return Objects.equals(targetType, cast.targetType);
}
@Override
public int computeHashCode() {
return Objects.hash(super.computeHashCode(), targetType);
}
@Override
public boolean isPositive() {
return true;
}
@Override
public int getMonotonicFunctionChildIndex() {
return 0;
}
@Override
public Expression withConstantArgs(Expression literal) {
return new Cast(literal, targetType, isExplicitType);
}
@Override
public boolean isMonotonic(Literal lower, Literal upper) {
// Both upward and downward casting of date types satisfy monotonicity.
if (child().getDataType() instanceof DateLikeType && targetType instanceof DateLikeType) {
return true;
}
return false;
}
}