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提交 e9c61128 authored 作者: Thomas Mueller's avatar Thomas Mueller
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Improved Oracle compatibility for CASE WHEN and DECODE.

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h2/src/docsrc/html/changelog.html
浏览文件 @ e9c61128
......@@ -18,7 +18,8 @@ Change Log
<h1>Change Log</h1>
<h2>Next Version (unreleased)</h2>
<ul><li>The statement "drop all objects" did not work if a table depends on a view via a constraint.
<ul><li>Improved Oracle compatibility for CASE WHEN and DECODE.
</li><li>The statement "drop all objects" did not work if a table depends on a view via a constraint.
</li><li>Subqueries or views with "order by" an alias expression could not be executed
due to a regression introduced in version 1.3.174.
</li><li>Issue 73: MySQL compatibility: support REPLACE, patch by Cemo Koc.
......
h2/src/main/org/h2/command/Parser.java
浏览文件 @ e9c61128
......@@ -1767,10 +1767,12 @@ public class Parser {
read("AND");
read("KEEP");
if (readIf("SHARE") || readIf("UPDATE") || readIf("EXCLUSIVE")) {
// ignore
}
read("LOCKS");
}
} else if (readIf("CS") || readIf("UR")) {
// ignore
}
}
}
......@@ -2597,12 +2599,7 @@ public class Parser {
// CASE must be processed before (,
// otherwise CASE(3) would be a function call, which it is
// not
if (isToken("WHEN")) {
r = readWhen(null);
} else {
Expression left = readExpression();
r = readWhen(left);
}
r = readCase();
} else if (readIf("(")) {
r = readFunction(null, name);
} else if (equalsToken("CURRENT_USER", name)) {
......@@ -2787,29 +2784,55 @@ public class Parser {
return r;
}
private Expression readWhen(Expression left) {
private Expression readCase() {
if (readIf("END")) {
readIf("CASE");
return ValueExpression.getNull();
}
if (readIf("ELSE")) {
Expression elsePart = readExpression();
Expression elsePart = readExpression().optimize(session);
read("END");
readIf("CASE");
return elsePart;
}
readIf("WHEN");
Expression when = readExpression();
if (left != null) {
when = new Comparison(session, Comparison.EQUAL, left, when);
int i;
Function function;
if (readIf("WHEN")) {
function = Function.getFunction(database, "CASE");
function.setParameter(0, null);
i = 1;
do {
function.setParameter(i++, readExpression());
read("THEN");
function.setParameter(i++, readExpression());
} while (readIf("WHEN"));
} else {
Expression expr = readExpression();
if (readIf("END")) {
readIf("CASE");
return ValueExpression.getNull();
}
if (readIf("ELSE")) {
Expression elsePart = readExpression().optimize(session);
read("END");
readIf("CASE");
return elsePart;
}
function = Function.getFunction(database, "CASE");
function.setParameter(0, expr);
i = 1;
read("WHEN");
do {
function.setParameter(i++, readExpression());
read("THEN");
Expression then = readExpression();
Expression elsePart = readWhen(left);
Function function = Function.getFunction(session.getDatabase(), "CASEWHEN");
function.setParameter(0, when);
function.setParameter(1, then);
function.setParameter(2, elsePart);
function.setParameter(i++, readExpression());
} while (readIf("WHEN"));
}
if (readIf("ELSE")) {
function.setParameter(i, readExpression());
}
read("END");
readIf("CASE");
function.doneWithParameters();
return function;
}
......
h2/src/main/org/h2/expression/Function.java
浏览文件 @ e9c61128
......@@ -821,9 +821,10 @@ public class Function extends Expression implements FunctionCall {
}
case DECODE: {
int index = -1;
for (int i = 1; i < args.length - 1; i += 2) {
for (int i = 1, len = args.length - 1; i < len; i += 2) {
if (database.areEqual(v0, getNullOrValue(session, args, values, i))) {
index = i + 1;
break;
}
}
if (index < 0 && args.length % 2 == 0) {
......@@ -876,18 +877,42 @@ public class Function extends Expression implements FunctionCall {
break;
}
case CASE: {
result = null;
int i = 0;
for (; i < args.length; i++) {
Value when = getNullOrValue(session, args, values, i++);
if (Boolean.TRUE.equals(when)) {
result = getNullOrValue(session, args, values, i);
Expression then = null;
if (v0 == null) {
// Searched CASE expression
// (null, when, then)
// (null, when, then, else)
// (null, when, then, when, then)
// (null, when, then, when, then, else)
for (int i = 1, len = args.length - 1; i < len; i += 2) {
Value when = args[i].getValue(session);
if (!(when == ValueNull.INSTANCE) && when.getBoolean().booleanValue()) {
then = args[i + 1];
break;
}
}
if (result == null) {
result = i < args.length ? getNullOrValue(session, args, values, i) : ValueNull.INSTANCE;
} else {
// Simple CASE expression
// (expr, when, then)
// (expr, when, then, else)
// (expr, when, then, when, then)
// (expr, when, then, when, then, else)
if (!(v0 == ValueNull.INSTANCE)) {
for (int i = 1, len = args.length - 1; i < len; i += 2) {
Value when = args[i].getValue(session);
if (database.areEqual(v0, when)) {
then = args[i + 1];
break;
}
}
}
}
if (then == null && args.length % 2 == 0) {
// then = elsePart
then = args[args.length - 1];
}
Value v = then == null ? ValueNull.INSTANCE : then.getValue(session);
result = v.convertTo(dataType);
break;
}
case ARRAY_GET: {
......@@ -971,7 +996,11 @@ public class Function extends Expression implements FunctionCall {
}
Value v = values[i];
if (v == null) {
v = values[i] = args[i].getValue(session);
Expression e = args[i];
if (e == null) {
return null;
}
v = values[i] = e.getValue(session);
}
return v;
}
......@@ -1700,9 +1729,11 @@ public class Function extends Expression implements FunctionCall {
@Override
public void mapColumns(ColumnResolver resolver, int level) {
for (Expression e : args) {
if (e != null) {
e.mapColumns(resolver, level);
}
}
}
/**
* Check if the parameter count is correct.
......@@ -1745,7 +1776,6 @@ public class Function extends Expression implements FunctionCall {
min = 2;
max = 3;
break;
case CASE:
case CONCAT:
case CONCAT_WS:
case CSVWRITE:
......@@ -1766,6 +1796,7 @@ public class Function extends Expression implements FunctionCall {
max = 2;
break;
case DECODE:
case CASE:
min = 3;
break;
default:
......@@ -1810,7 +1841,11 @@ public class Function extends Expression implements FunctionCall {
public Expression optimize(Session session) {
boolean allConst = info.deterministic;
for (int i = 0; i < args.length; i++) {
Expression e = args[i].optimize(session);
Expression e = args[i];
if (e == null) {
continue;
}
e = e.optimize(session);
args[i] = e;
if (!e.isConstant()) {
allConst = false;
......@@ -1824,24 +1859,12 @@ public class Function extends Expression implements FunctionCall {
case NULLIF:
case COALESCE:
case LEAST:
case GREATEST:
case DECODE: {
case GREATEST: {
t = Value.UNKNOWN;
s = 0;
p = 0;
d = 0;
int i = 0;
for (Expression e : args) {
if (info.type == DECODE) {
if (i < 2 || ((i % 2 == 1) && (i != args.length - 1))) {
// decode(a, b, whenB)
// decode(a, b, whenB, else)
// decode(a, b, whenB, c, whenC)
// decode(a, b, whenB, c, whenC, end)
i++;
continue;
}
}
if (e != ValueExpression.getNull()) {
int type = e.getType();
if (type != Value.UNKNOWN && type != Value.NULL) {
......@@ -1851,7 +1874,48 @@ public class Function extends Expression implements FunctionCall {
d = Math.max(d, e.getDisplaySize());
}
}
i++;
}
if (t == Value.UNKNOWN) {
t = Value.STRING;
s = 0;
p = Integer.MAX_VALUE;
d = Integer.MAX_VALUE;
}
break;
}
case CASE:
case DECODE: {
t = Value.UNKNOWN;
s = 0;
p = 0;
d = 0;
// (expr, when, then)
// (expr, when, then, else)
// (expr, when, then, when, then)
// (expr, when, then, when, then, else)
for (int i = 2, len = args.length; i < len; i += 2) {
Expression then = args[i];
if (then != ValueExpression.getNull()) {
int type = then.getType();
if (type != Value.UNKNOWN && type != Value.NULL) {
t = Value.getHigherOrder(t, type);
s = Math.max(s, then.getScale());
p = Math.max(p, then.getPrecision());
d = Math.max(d, then.getDisplaySize());
}
}
}
if (args.length % 2 == 0) {
Expression elsePart = args[args.length - 1];
if (elsePart != ValueExpression.getNull()) {
int type = elsePart.getType();
if (type != Value.UNKNOWN && type != Value.NULL) {
t = Value.getHigherOrder(t, type);
s = Math.max(s, elsePart.getScale());
p = Math.max(p, elsePart.getPrecision());
d = Math.max(d, elsePart.getDisplaySize());
}
}
}
if (t == Value.UNKNOWN) {
t = Value.STRING;
......@@ -2086,6 +2150,19 @@ public class Function extends Expression implements FunctionCall {
@Override
public String getSQL() {
StatementBuilder buff = new StatementBuilder(info.name);
if (info.type == CASE) {
if (args[0] != null) {
buff.append(" ").append(args[0].getSQL());
}
for (int i = 1, len = args.length - 1; i < len; i += 2) {
buff.append(" WHEN ").append(args[i].getSQL());
buff.append(" THEN ").append(args[i + 1].getSQL());
}
if (args.length % 2 == 0) {
buff.append(" ELSE ").append(args[args.length - 1].getSQL());
}
return buff.append(" END").toString();
}
buff.append('(');
switch (info.type) {
case CAST: {
......
h2/src/test/org/h2/test/testScript.sql
浏览文件 @ e9c61128
......@@ -4,6 +4,24 @@
-- Initial Developer: H2 Group
--
--- special grammar and test cases ---------------------------------------------------------------------------------------------
create sequence seq;
> ok
select case seq.nextval when 2 then 'two' when 3 then 'three' when 1 then 'one' else 'other' end result from dual;
> RESULT
> ------
> one
> rows: 1
drop sequence seq;
> ok
select decode(1, 1, '1', 1, '11') r from dual;
> R
> -
> 1
> rows: 1
create table test(x int);
> ok
......
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