xuzifu666 commented on code in PR #4460:
URL: https://github.com/apache/calcite/pull/4460#discussion_r2312006966
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core/src/main/java/org/apache/calcite/rex/RexSimplify.java:
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@@ -500,17 +501,67 @@ private RexNode simplifyDivide(RexCall e) {
private RexNode simplifyLike(RexCall e, RexUnknownAs unknownAs) {
if (e.operands.get(1) instanceof RexLiteral) {
final RexLiteral literal = (RexLiteral) e.operands.get(1);
- if ("%".equals(literal.getValueAs(String.class))) {
- // "x LIKE '%'" simplifies to "x = x"
+ String likeStr = requireNonNull(literal.getValueAs(String.class));
+ Pattern pattern = Pattern.compile("%+");
+ String value = pattern.matcher(likeStr).replaceAll("%");
+ if ("%".equals(value)) {
+ // "x LIKE '%'" or "x LIKE '%...'" simplifies to "x = x"
final RexNode x = e.operands.get(0);
return simplify(
rexBuilder.makeCall(
e.getParserPosition(), SqlStdOperatorTable.EQUALS, x, x),
unknownAs);
}
+ // simplify "x LIKE '%%\%%a%%%'" to "x LIKE '%\%%a%'", default escape is
'\'
+ if (e.operands.size() == 2) {
+ e = (RexCall) rexBuilder
+ .makeCall(e.getParserPosition(), e.getOperator(),
e.operands.get(0),
+ rexBuilder.makeLiteral(simplifyLikeString(likeStr, '\\',
'%')));
+ }
+ if (e.operands.size() == 3 && e.operands.get(2) instanceof RexLiteral) {
+ final RexLiteral escapeLiteral = (RexLiteral) e.operands.get(2);
+ Character escape =
requireNonNull(escapeLiteral.getValueAs(Character.class));
+ e = (RexCall) rexBuilder
+ .makeCall(e.getParserPosition(), e.getOperator(),
e.operands.get(0),
+ rexBuilder.makeLiteral(simplifyLikeString(likeStr, escape,
'%')),
+ escapeLiteral);
+ }
}
return simplifyGenericNode(e);
}
+ /**
+ * Simplifies like string with escape.
+ * A like '%%#%%A%%' escape '#' should simplify to A like '%#%%A%' escape
'#'.
+ */
+ private String simplifyLikeString(String content, char escape, char
wildcard) {
Review Comment:
OK, I had added a jira ticket for it
https://issues.apache.org/jira/browse/CALCITE-7153
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