public StringExpression substring(Expression<Integer> beginIndex) {
        return Expressions.stringOperation(Ops.SUBSTR_1ARG, mixin, beginIndex);
    }
Create a {@code this.substring(beginIndex)} expression

@param beginIndex inclusive start index
@return this.substring(beginIndex)
@see java.lang.String#substring(int)
querydsl-core/src/main/java/com/querydsl/core/types/dsl/StringExpression.java