Ensure the columns of views and sub-selects in the FROM clause of a select are always assigned implicit collation sequences, just as table columns are. Fix for [a7debbe0].

FossilOrigin-Name: b9ec72203c19c2b95e648ac1dfad74eec98d4ff82581cdc10dc4221ba551728f

test/tkt-a7debbe0.test

@@ -0,0 +1,103 @@
+# 2019 September 10
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library. In particular,
+# that problems related to ticket a7debbe0ad1 have been fixed.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix tkt-a7debbe0
+
+foreach tn {1 2} {
+  reset_db
+  if {$tn==1} {
+    # Disable the flattener
+    optimization_control db query-flattener 0
+  } else {
+    # Enable the flattener
+    optimization_control db query-flattener 1
+  }
+
+  do_execsql_test $tn.1.0 {
+    CREATE TABLE t0(xyz INTEGER);
+    INSERT INTO t0(xyz) VALUES(456);
+    CREATE VIEW v2(a, B) AS 
+        SELECT 'a', 'B' COLLATE NOCASE FROM t0;
+    CREATE TABLE t2(a, B COLLATE NOCASE);
+    INSERT INTO t2 VALUES('a', 'B');
+    CREATE VIEW v3(a, B) AS
+        SELECT 'a' COLLATE BINARY, 'B' COLLATE NOCASE FROM t0;
+
+    CREATE VIEW v4(a, B) AS
+        SELECT 'a', +CAST('B' COLLATE NOCASE AS TEXT) FROM t0;
+
+    CREATE VIEW v5(a, B) AS
+        SELECT 'a', ('B' COLLATE NOCASE) || '' FROM t0;
+  }
+
+  # Table t2 and views v2 through v5 should all be equivalent.
+  do_execsql_test $tn.1.1.1 { SELECT a   >= B FROM t2;         } 1
+  do_execsql_test $tn.1.1.2 { SELECT 'a' >= 'B' COLLATE NOCASE } 0
+  do_execsql_test $tn.1.1.3 { SELECT a   >= B FROM v2          } 1
+  do_execsql_test $tn.1.1.4 { SELECT a   >= B FROM v3          } 1
+  do_execsql_test $tn.1.1.5 { SELECT a   >= B FROM v4          } 1
+  do_execsql_test $tn.1.1.6 { SELECT a   >= B FROM v5          } 1
+
+  do_execsql_test $tn.1.2.1 { SELECT B   < a FROM t2           } 0
+  do_execsql_test $tn.1.2.2 { SELECT 'B' COLLATE NOCASE < 'a'  } 0
+  do_execsql_test $tn.1.2.3 { SELECT B   < a FROM v2           } 0
+  do_execsql_test $tn.1.2.4 { SELECT B   < a FROM v3           } 0
+  do_execsql_test $tn.1.2.5 { SELECT a  < B FROM v4           } 0
+  do_execsql_test $tn.1.2.6 { SELECT a  < B FROM v5           } 0
+
+  #-------------------------------------------------------------------------
+  do_execsql_test $tn.2.0 {
+    CREATE TABLE t5(a, b COLLATE NOCASE);
+    INSERT INTO t5 VALUES(1, 'XYZ');
+  }
+
+  # Result should be 0, as column "xyz" from the sub-query has implicit
+  # collation sequence BINARY.
+  do_execsql_test $tn.2.1 {
+    SELECT xyz==b FROM ( SELECT a, 'xyz' AS xyz FROM t5 ), t5;
+  } {0}
+
+  # Result should be 1, as literal 'xyz' has no collation sequence, so
+  # the comparison uses the implicit collation sequence of the RHS - NOCASE.
+  do_execsql_test $tn.2.2 {
+    SELECT 'xyz'==b FROM ( SELECT a, 'xyz' AS xyz FROM t5 ), t5;
+  } {1}
+
+  #-----------------------------------------------------------------------
+  # The test case submitted with the ticket.
+  #
+  do_execsql_test $tn.3.0 {
+    DROP TABLE t0;
+    DROP VIEW v2;
+
+    CREATE TABLE t0(c0);
+    INSERT INTO t0(c0) VALUES('');
+    CREATE VIEW v2(c0, c1) AS 
+        SELECT 'B' COLLATE NOCASE, 'a' FROM t0 ORDER BY t0.c0;
+    SELECT SUM(count) FROM (
+      SELECT v2.c1 BETWEEN v2.c0 AND v2.c1 as count FROM v2
+    );
+  } 1
+
+  # The result is 1, as the collation used is the implicit collation sequence
+  # of v2.c1 - BINARY.
+  do_execsql_test $tn.3.1 {
+    SELECT v2.c1 BETWEEN v2.c0 AND v2.c1 as count FROM v2;
+  } 1
+}
+
+finish_test
+