com.hazelcast.org.apache.calcite.sql.fun.SqlExtendOperator Maven / Gradle / Ivy
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* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.org.licenses/LICENSE-2.0
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package com.hazelcast.org.apache.calcite.sql.fun;
import com.hazelcast.org.apache.calcite.linq4j.Ord;
import com.hazelcast.org.apache.calcite.sql.SqlCall;
import com.hazelcast.org.apache.calcite.sql.SqlInternalOperator;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import com.hazelcast.org.apache.calcite.sql.SqlNode;
import com.hazelcast.org.apache.calcite.sql.SqlNodeList;
import com.hazelcast.org.apache.calcite.sql.SqlOperator;
import com.hazelcast.org.apache.calcite.sql.SqlWriter;
/** {@code EXTEND} operator.
*
* Adds columns to a table's schema, as in
* {@code SELECT ... FROM emp EXTEND (horoscope VARCHAR(100))}.
*
*
Not standard SQL. Added to Calcite to support Phoenix, but can be used to
* achieve schema-on-query against other adapters.
*/
class SqlExtendOperator extends SqlInternalOperator {
SqlExtendOperator() {
super("EXTEND", SqlKind.EXTEND, MDX_PRECEDENCE);
}
@Override public void unparse(SqlWriter writer, SqlCall call, int leftPrec,
int rightPrec) {
final SqlOperator operator = call.getOperator();
assert call.operandCount() == 2;
final SqlWriter.Frame frame =
writer.startList(SqlWriter.FrameTypeEnum.SIMPLE);
call.operand(0).unparse(writer, leftPrec, operator.getLeftPrec());
writer.setNeedWhitespace(true);
writer.sep(operator.getName());
final SqlNodeList list = call.operand(1);
final SqlWriter.Frame frame2 = writer.startList("(", ")");
for (Ord node2 : Ord.zip(list)) {
if (node2.i > 0 && node2.i % 2 == 0) {
writer.sep(",");
}
node2.e.unparse(writer, 2, 3);
}
writer.endList(frame2);
writer.endList(frame);
}
}