DateTrunc.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.functions.scalar;
import org.apache.doris.catalog.FunctionSignature;
import org.apache.doris.nereids.exceptions.AnalysisException;
import org.apache.doris.nereids.trees.expressions.Expression;
import org.apache.doris.nereids.trees.expressions.functions.CustomSignature;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullLiteral;
import org.apache.doris.nereids.trees.expressions.functions.PropagateNullable;
import org.apache.doris.nereids.trees.expressions.functions.RoundingMonotonic;
import org.apache.doris.nereids.trees.expressions.functions.RoundingMonotonic.RoundingType;
import org.apache.doris.nereids.trees.expressions.literal.IntegerLiteral;
import org.apache.doris.nereids.trees.expressions.literal.Literal;
import org.apache.doris.nereids.trees.expressions.literal.StringLikeLiteral;
import org.apache.doris.nereids.trees.expressions.literal.format.DateTimeChecker;
import org.apache.doris.nereids.trees.expressions.shape.BinaryExpression;
import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor;
import org.apache.doris.nereids.types.DataType;
import org.apache.doris.nereids.types.DateTimeV2Type;
import org.apache.doris.nereids.types.TimeStampTzType;
import org.apache.doris.nereids.types.VarcharType;
import org.apache.doris.nereids.util.ExpressionUtils;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import java.util.List;
import java.util.Optional;
/**
* ScalarFunction 'date_trunc'. This class is generated by GenerateFunction.
*/
public class DateTrunc extends ScalarFunction
implements BinaryExpression, PropagateNullLiteral, PropagateNullable, RoundingMonotonic, CustomSignature {
private static final List<String> LEGAL_TIME_UNIT =
ImmutableList.of("year", "quarter", "month", "week", "day", "hour", "minute", "second");
/**
* constructor with 2 arguments.
*/
public DateTrunc(Expression arg0, Expression arg1) {
super("date_trunc", arg0, arg1);
}
/** constructor for withChildren and reuse signature */
private DateTrunc(ScalarFunctionParams functionParams) {
super(functionParams);
}
@Override
public Expression prepareBeforeTypeCoercion() {
// When an argument is a date, the other one is the time unit, and the signature does not need its value.
if (getArgument(0).getDataType().isDateLikeType() || getArgument(1).getDataType().isDateLikeType()) {
return this;
}
// Otherwise customSignature tells the time unit from the date value by the literal time unit, so fold a
// constant string that evaluates to a time unit, unless the other argument already is one. A string date
// value is kept unfolded, because folding it would change the derived return type.
return withChildren((argument, index) -> {
if (!argument.getDataType().isStringLikeType() || isTimeUnit(getArgument(1 - index))) {
return argument;
}
Expression folded = ExpressionUtils.foldConstantArgument(argument);
return isTimeUnit(folded) ? folded : argument;
});
}
private static boolean isTimeUnit(Expression expression) {
return expression instanceof StringLikeLiteral
&& LEGAL_TIME_UNIT.contains(((StringLikeLiteral) expression).getStringValue().toLowerCase());
}
private static boolean isConstantString(Expression expression) {
return expression.isConstant() && expression.getDataType().isStringLikeType();
}
/**
* Tells the date value from the time unit. Returns the index of the date argument, or -1 when neither
* argument identifies its role on FE, e.g. two string constants only BE can evaluate.
*/
private int dateArgumentIndex() {
for (int i = 0; i < 2; i++) {
if (getArgument(i).getDataType().isDateLikeType()) {
return i;
}
}
// A nonconstant argument, e.g. a VARCHAR column, can only be the date value.
for (int i = 0; i < 2; i++) {
if (!getArgument(i).isConstant()) {
return i;
}
}
// prepareBeforeTypeCoercion folded the constant that evaluates to a time unit, so a literal time unit
// tells that the other argument is the date value.
for (int i = 0; i < 2; i++) {
if (isTimeUnit(getArgument(i))) {
return 1 - i;
}
}
// A string FE evaluates to anything else is the date value, and the other argument is then the time unit,
// which BE validates when FE cannot evaluate it.
for (int i = 0; i < 2; i++) {
if (ExpressionUtils.foldConstantArgument(getArgument(i)) instanceof StringLikeLiteral) {
return i;
}
}
return -1;
}
@Override
public void checkLegalityBeforeTypeCoercion() {
int dateIndex = dateArgumentIndex();
if (dateIndex < 0 || !isConstantString(getArgument(1 - dateIndex))) {
throw new AnalysisException("the time unit parameter of "
+ getName() + " function must be a string constant: " + toSql());
}
// Validate the time unit value FE can evaluate here, because constant folding may remove this function
// before any later check. BE validates a time unit FE cannot evaluate.
Expression timeUnit = ExpressionUtils.foldConstantArgument(getArgument(1 - dateIndex));
if (timeUnit instanceof StringLikeLiteral && !isTimeUnit(timeUnit)) {
throw new AnalysisException("date_trunc function time unit param only support argument is "
+ String.join("|", LEGAL_TIME_UNIT));
}
}
/**
* withChildren.
*/
@Override
public DateTrunc withChildren(List<Expression> children) {
Preconditions.checkArgument(children.size() == 2);
return new DateTrunc(getFunctionParams(children));
}
@Override
public FunctionSignature customSignature() {
// should never return V1 Type
int dateIndex = dateArgumentIndex();
if (dateIndex < 0) {
// checkLegalityBeforeTypeCoercion rejects the call, so just return a signature here
return FunctionSignature.ret(DateTimeV2Type.WILDCARD)
.args(VarcharType.SYSTEM_DEFAULT, DateTimeV2Type.WILDCARD);
}
Expression date = getArgument(dateIndex);
DataType type;
if (date.getDataType() instanceof TimeStampTzType) {
// Handle TimeStampTzType first, because getCurrentType() would convert it to DateTimeV2Type
type = date.getDataType();
} else if (date.getDataType().isDateLikeType()) {
type = DataType.getCurrentType(date.getDataType());
} else if (date instanceof StringLikeLiteral
&& DateTimeChecker.hasTimeZone(((StringLikeLiteral) date).getStringValue())) {
// a literal datetime string with timezone information
type = TimeStampTzType.SYSTEM_DEFAULT;
} else {
type = DateTimeV2Type.WILDCARD;
}
return dateIndex == 0 ? FunctionSignature.ret(type).args(type, VarcharType.SYSTEM_DEFAULT)
: FunctionSignature.ret(type).args(VarcharType.SYSTEM_DEFAULT, type);
}
@Override
public <R, C> R accept(ExpressionVisitor<R, C> visitor, C context) {
return visitor.visitDateTrunc(this, context);
}
@Override
public boolean isPositive() {
return true;
}
@Override
public RoundingType getRoundingType() {
return RoundingType.FLOOR;
}
@Override
public Optional<Expression> nextBucketBoundary(Literal value) {
int dateArgumentIndex = getMonotonicFunctionChildIndex();
Expression unit = child(dateArgumentIndex == 0 ? 1 : 0);
if (!(unit instanceof StringLikeLiteral)) {
return Optional.empty();
}
IntegerLiteral one = new IntegerLiteral(1);
switch (((StringLikeLiteral) unit).getStringValue().toLowerCase()) {
case "year":
return Optional.of(new YearsAdd(value, one));
case "quarter":
return Optional.of(new QuartersAdd(value, one));
case "month":
return Optional.of(new MonthsAdd(value, one));
case "week":
return Optional.of(new WeeksAdd(value, one));
case "day":
return Optional.of(new DaysAdd(value, one));
case "hour":
return Optional.of(new HoursAdd(value, one));
case "minute":
return Optional.of(new MinutesAdd(value, one));
case "second":
return Optional.of(new SecondsAdd(value, one));
default:
return Optional.empty();
}
}
@Override
public boolean isRoundingRelationGuaranteed() {
int dateArgumentIndex = getMonotonicFunctionChildIndex();
Expression unit = child(dateArgumentIndex == 0 ? 1 : 0);
return unit instanceof StringLikeLiteral
&& LEGAL_TIME_UNIT.contains(((StringLikeLiteral) unit).getStringValue().toLowerCase());
}
@Override
public int getMonotonicFunctionChildIndex() {
return getArgument(0).getDataType().isDateLikeType() ? 0 : 1;
}
@Override
public Expression withConstantArgs(Expression literal) {
return getArgument(0).getDataType().isDateLikeType()
? new DateTrunc(literal, child(1)) : new DateTrunc(child(0), literal);
}
}