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[#3511] Improve DISTINCT predicate emulation through INTERSECT

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This commit is contained in:
Lukas Eder 2014-08-12 17:23:33 +02:00
parent f587997ebc
commit a1a5b7e06e
1 changed files with 14 additions and 3 deletions
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17
jOOQ/src/main/java/org/jooq/impl/IsDistinctFrom.java
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@ -41,6 +41,7 @@
package org.jooq.impl;
import static java.util.Arrays.asList;
import static org.jooq.Comparator.IS_DISTINCT_FROM;
// ...
// ...
import static org.jooq.SQLDialect.CUBRID;
@ -56,7 +57,10 @@ import static org.jooq.SQLDialect.SQLITE;
// ...
import static org.jooq.impl.DSL.condition;
import static org.jooq.impl.DSL.decode;
import static org.jooq.impl.DSL.exists;
import static org.jooq.impl.DSL.notExists;
import static org.jooq.impl.DSL.one;
import static org.jooq.impl.DSL.select;
import static org.jooq.impl.DSL.zero;
import org.jooq.Clause;
@ -109,8 +113,15 @@ class IsDistinctFrom<T> extends AbstractCondition {
*/
private final QueryPartInternal delegate(Configuration configuration) {
// These dialects need to emulate the IS DISTINCT FROM predicate
// [#3511] These dialects need to emulate the IS DISTINCT FROM predicate, optimally using INTERSECT...
if (asList(CUBRID, DERBY).contains(configuration.dialect().family())) {
return (comparator == IS_DISTINCT_FROM)
? (QueryPartInternal) notExists(select(lhs).intersect(select(rhs)))
: (QueryPartInternal) exists(select(lhs).intersect(select(rhs)));
}
// ... or using a more verbose CASE expression
else if (asList().contains(configuration.dialect().family())) {
if (caseExpression == null) {
if (comparator == Comparator.IS_DISTINCT_FROM) {
caseExpression = (QueryPartInternal) decode()
@ -138,7 +149,7 @@ class IsDistinctFrom<T> extends AbstractCondition {
// MySQL knows the <=> operator
else if (asList(MARIADB, MYSQL).contains(configuration.dialect())) {
if (mySQLCondition == null) {
if (comparator == Comparator.IS_DISTINCT_FROM) {
if (comparator == IS_DISTINCT_FROM) {
mySQLCondition = (QueryPartInternal) condition("{not}({0} <=> {1})", lhs, rhs);
}
else {
@ -152,7 +163,7 @@ class IsDistinctFrom<T> extends AbstractCondition {
// SQLite knows the IS / IS NOT predicate
else if (SQLITE == configuration.dialect()) {
if (sqliteCondition == null) {
if (comparator == Comparator.IS_DISTINCT_FROM) {
if (comparator == IS_DISTINCT_FROM) {
sqliteCondition = (QueryPartInternal) condition("{0} {is not} {1}", lhs, rhs);
}
else {