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[jOOQ/jOOQ#14307] Emulate LIMIT 0 where not supported

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This commit is contained in:
Lukas Eder 2024-02-07 16:42:44 +01:00
parent bf561461e3
commit d1c2effe2e
2 changed files with 26 additions and 6 deletions
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16
jOOQ/src/main/java/org/jooq/impl/Limit.java
View File

@ -319,7 +319,7 @@ final class Limit extends AbstractQueryPart implements UTransient {
.sql(' ').visit(offsetOrZero)
.sql(' ').visit(K_ROWS);
if (!limitZero()) {
if (!limitAbsent()) {
ctx.formatSeparator()
.visit(K_FETCH_NEXT).sql(' ').visit(limit);
@ -335,7 +335,7 @@ final class Limit extends AbstractQueryPart implements UTransient {
private final void acceptDefault(Context<?> ctx, CastMode castMode) {
ctx.castMode(NEVER);
if (!limitZero())
if (!limitAbsent())
ctx.formatSeparator()
.visit(K_LIMIT)
.sql(' ').visit(limit);
@ -381,19 +381,27 @@ final class Limit extends AbstractQueryPart implements UTransient {
/**
* Whether the limit is absent
*/
final boolean limitAbsent() {
return limit == null;
}
/**
* Whether this limit has a limit of zero
*/
final boolean limitZero() {
return limit == null;
return !limitAbsent()
&& Long.valueOf(0L).equals(getLimit());
}
/**
* Whether this limit has a limit of one
*/
final boolean limitOne() {
return !limitZero()
return !limitAbsent()
&& !withTies()
&& !percent()
&& Long.valueOf(1L).equals(getLimit());

16
jOOQ/src/main/java/org/jooq/impl/SelectQueryImpl.java
View File

@ -378,6 +378,8 @@ final class SelectQueryImpl<R extends Record> extends AbstractResultQuery<R> imp
static final Set<SQLDialect> NO_SUPPORT_FOR_UPDATE_OF_FIELDS = SQLDialect.supportedBy(MYSQL, POSTGRES, YUGABYTEDB);
static final Set<SQLDialect> NO_SUPPORT_UNION_ORDER_BY_ALIAS = SQLDialect.supportedBy(FIREBIRD);
static final Set<SQLDialect> NO_SUPPORT_WITH_READ_ONLY = SQLDialect.supportedBy(CUBRID, DERBY, FIREBIRD, H2, HSQLDB, MARIADB, MYSQL, POSTGRES, SQLITE, YUGABYTEDB);
static final Set<SQLDialect> NO_SUPPORT_LIMIT_ZERO = SQLDialect.supportedBy(DERBY, HSQLDB);
@ -2156,7 +2158,7 @@ final class SelectQueryImpl<R extends Record> extends AbstractResultQuery<R> imp
@SuppressWarnings("unchecked")
private final Condition limitWindowFunctionCondition(Field<Integer> limitWindowFunction) {
return getLimit().limitZero()
return getLimit().limitAbsent()
? limitWindowFunction.gt((Field<Integer>) getLimit().getLowerRownum())
: limitWindowFunction
.between((Field<Integer>) getLimit().getLowerRownum().add(inline(1)))
@ -3469,7 +3471,8 @@ final class SelectQueryImpl<R extends Record> extends AbstractResultQuery<R> imp
if (TRUE.equals(ctx.data(DATA_RENDER_TRAILING_LIMIT_IF_APPLICABLE))) {
if (actualLimit.isApplicable()) {
ctx.visit(actualLimit);
if (!(actualLimit.limitZero() && NO_SUPPORT_LIMIT_ZERO.contains(ctx.dialect())))
ctx.visit(actualLimit);
}
// [#13509] Force a LIMIT clause to prevent optimisation of "unnecessary" ORDER BY
@ -3560,6 +3563,9 @@ final class SelectQueryImpl<R extends Record> extends AbstractResultQuery<R> imp
@ -4382,6 +4388,9 @@ final class SelectQueryImpl<R extends Record> extends AbstractResultQuery<R> imp
if (NO_SUPPORT_LIMIT_ZERO.contains(ctx.dialect()) && limit.limitZero() && !isGrouping())
result.addConditions(falseCondition());
return result;
}
@ -4517,6 +4526,9 @@ final class SelectQueryImpl<R extends Record> extends AbstractResultQuery<R> imp
if (isGrouping() && !getOrderBy().isEmpty() && !getSeek().isEmpty() && unionOp.isEmpty())
result.addConditions(getSeekCondition(ctx));
if (NO_SUPPORT_LIMIT_ZERO.contains(ctx.dialect()) && limit.limitZero() && isGrouping())
result.addConditions(falseCondition());
return result;
}