Return NULL from ARRAY_CONTAINS(NULL, value) for better compatibility

h2/src/docsrc/help/help.csv

@@ -4155,7 +4155,7 @@ ISO_YEAR(CREATED)
 ARRAY_GET(arrayExpression, indexExpression)
 ","
 Returns one element of an array.
-This method returns a string.
+Returns NULL if there is no such element or array is NULL.
 ","
 CALL ARRAY_GET(('Hello', 'World'), 2)
 "
@@ -4164,6 +4164,7 @@ CALL ARRAY_GET(('Hello', 'World'), 2)
 ARRAY_LENGTH(arrayExpression)
 ","
 Returns the length of an array.
+Returns NULL if the specified array is NULL.
 ","
 CALL ARRAY_LENGTH(('Hello', 'World'))
 "
@@ -4171,7 +4172,8 @@ CALL ARRAY_LENGTH(('Hello', 'World'))
 "Functions (System)","ARRAY_CONTAINS","
 ARRAY_CONTAINS(arrayExpression, value)
 ","
-Returns a boolean true if the array contains the value.
+Returns a boolean TRUE if the array contains the value or FALSE if it does not contain it.
+Returns NULL if the specified array is NULL.
 ","
 CALL ARRAY_CONTAINS(('Hello', 'World'), 'Hello')
 "

h2/src/main/org/h2/expression/Function.java

@@ -414,7 +414,7 @@ public class Function extends Expression implements FunctionCall {
         addFunctionNotDeterministic("CURRVAL", CURRVAL,
                 VAR_ARGS, Value.LONG);
         addFunction("ARRAY_GET", ARRAY_GET,
-                2, Value.STRING);
+                2, Value.NULL);
         addFunction("ARRAY_CONTAINS", ARRAY_CONTAINS,
                 2, Value.BOOLEAN, false, true, true);
         addFunction("CSVREAD", CSVREAD,
@@ -1059,6 +1059,8 @@ public class Function extends Expression implements FunctionCall {
                         break;
                     }
                 }
+            } else {
+                result = ValueNull.INSTANCE;
             }
             break;
         }

h2/src/test/org/h2/test/scripts/functions/system/array-contains.sql

@@ -22,7 +22,7 @@ select array_contains((null, 'two'), null);
 >> TRUE
 
 select array_contains(null, 'one');
->> FALSE
+>> null
 
 select array_contains(((1, 2), (3, 4)), (1, 2));
 >> TRUE