pengzhiwei2018 commented on a change in pull request #1168: [CALCITE-3005]
Implement string functions: LEFT, RIGHT
URL: https://github.com/apache/calcite/pull/1168#discussion_r276167803
##########
File path: core/src/main/java/org/apache/calcite/runtime/SqlFunctions.java
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@@ -243,6 +243,26 @@ public static int ascii(String s) {
? 0 : s.codePointAt(0);
}
+ /** SQL LEFT(string, int) function. */
+ public static String left(String s, int n) {
+ if (n < 0) {
+ return "";
+ } else {
+ int len = s.length();
Review comment:
And another thing is that in the description of this issue Calcite-3005,
this function should return null if any of the input is null. So if `null` is
not allowed for this function, the description should be modified. The same
with the "_docs/reference.md".
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