I have a sql where cluase:
a > 1 and b < 1 and c = 3
In this case I want to remove the a>1
, how could I rewrite it to
1 = 1 and b < 1 and c =3
I have try the ExpressionVisitor, but couldn't rewrite the Expression
You can simply replace the where part of a SQL by using something like:
((PlainSelect)selectBody).setWhere(CCJSqlParserUtil.parseCondExpression("mycol = 10"));
but if you want to use the where expression itself and want to find in it the expression a > 1, then you have to use something like
Select stmt = (Select) CCJSqlParserUtil.parse("select * from a where a > 1 and b < 1 and c = 3");
System.out.println("before " + stmt.toString());
((PlainSelect) stmt.getSelectBody()).getWhere().accept(new ExpressionVisitorAdapter() {
@Override
public void visitBinaryExpression(BinaryExpression expr) {
if ("a > 1".equals(expr.getLeftExpression().toString())) {
try {
expr.setLeftExpression(CCJSqlParserUtil.parseCondExpression("1=1"));
} catch (JSQLParserException ex) {
Logger.getLogger(SimpleSqlParser39ReplaceExpressionInWhere.class.getName()).log(Level.SEVERE, null, ex);
}
}
super.visitBinaryExpression(expr);
}
});
System.out.println("after " + stmt.toString());
This is not a complete solution since you have to check the right expression as well. Since you are indeed not able to modify the binary expression a > 1 itself you have to look for the enclosing expression and replace it there. So that's the main idea.
By the way this is the output of this little snippet:
before SELECT * FROM a WHERE a > 1 AND b < 1 AND c = 3
after SELECT * FROM a WHERE 1 = 1 AND b < 1 AND c = 3
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