Improvement to the way that affinity is determined for columns of a

compound subquery.  The affinity is the affinity of the left-most
arm of the compound subquery that has an affinity other than NONE, adjusted
to accommodate the data types coming out of the other arms.

Author: D. Richard Hipp

src/select.c

@@ -2336,17 +2336,22 @@ void sqlite3SubqueryColumnTypes(
   for(i=0, pCol=pTab->aCol; i<pTab->nCol; i++, pCol++){
     const char *zType;
     i64 n;
+    int m = 0;
+    Select *pS2 = pSelect;
     pTab->tabFlags |= (pCol->colFlags & COLFLAG_NOINSERT);
     p = a[i].pExpr;
     /* pCol->szEst = ... // Column size est for SELECT tables never used */
     pCol->affinity = sqlite3ExprAffinity(p);
+    while( pCol->affinity<=SQLITE_AFF_NONE && pS2->pNext!=0 ){
+      m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
+      pS2 = pS2->pNext;
+      pCol->affinity = sqlite3ExprAffinity(pS2->pEList->a[i].pExpr);
+    }
     if( pCol->affinity<=SQLITE_AFF_NONE ){
       pCol->affinity = aff;
     }
-    if( pCol->affinity>=SQLITE_AFF_TEXT && pSelect->pNext ){
-      int m = 0;
-      Select *pS2;
-      for(m=0, pS2=pSelect->pNext; pS2; pS2=pS2->pNext){
+    if( pCol->affinity>=SQLITE_AFF_TEXT && (pS2->pNext || pS2!=pSelect) ){
+      for(pS2=pS2->pNext; pS2; pS2=pS2->pNext){
         m |= sqlite3ExprDataType(pS2->pEList->a[i].pExpr);
       }
       if( pCol->affinity==SQLITE_AFF_TEXT && (m&0x01)!=0 ){

test/subquery.test

@@ -651,5 +651,64 @@ do_eqp_test subquery-10.2 {
 # `--SEARCH t1 USING INDEX x12 (aa=?)
 #
 
+#-----------------------------------------------------------------------------
+# 2024-04-25 Column affinities for columns of compound subqueries
+#
+reset_db
+sqlite3_test_control SQLITE_TESTCTRL_INTERNAL_FUNCTIONS db
+do_execsql_test subquery-11.1 {
+  CREATE TABLE t1(ix INT, rx REAL, bx BLOB, tx TEXT, ax);
+  INSERT INTO t1 VALUES(1,1.0,x'31','x',NULL);
+  WITH c(a) AS (SELECT 'y' UNION SELECT tx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT tx FROM t1 UNION SELECT 'y') SELECT affinity(a) FROM c;
+} {text text text text}
+do_execsql_test subquery-11.2 {
+  WITH c(a) AS (SELECT 2 UNION SELECT tx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT tx FROM t1 UNION SELECT 2) SELECT affinity(a) FROM c;
+} {blob blob blob blob}
+do_execsql_test subquery-11.3 {
+  WITH c(a) AS (SELECT 2.0 UNION SELECT tx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT tx FROM t1 UNION SELECT 2.0) SELECT affinity(a) FROM c;
+} {blob blob blob blob}
+do_execsql_test subquery-11.4 {
+  WITH c(a) AS (SELECT null UNION SELECT tx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT tx FROM t1 UNION SELECT null) SELECT affinity(a) FROM c;
+} {text text text text}
+do_execsql_test subquery-11.5 {
+  WITH c(a) AS (SELECT x'32' UNION SELECT tx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT tx FROM t1 UNION SELECT x'32') SELECT affinity(a) FROM c;
+} {text text text text}
+do_execsql_test subquery-11.6 {
+  WITH c(a) AS (SELECT 3 UNION SELECT ix FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT ix FROM t1 UNION SELECT 3) SELECT affinity(a) FROM c;
+} {integer integer integer integer}
+do_execsql_test subquery-11.7 {
+  WITH c(a) AS (SELECT 3.0 UNION SELECT ix FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT ix FROM t1 UNION SELECT 3.0) SELECT affinity(a) FROM c;
+} {integer integer integer integer}
+do_execsql_test subquery-11.8 {
+  WITH c(a) AS (SELECT '3' UNION SELECT ix FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT ix FROM t1 UNION SELECT '3') SELECT affinity(a) FROM c;
+} {blob blob blob blob}
+do_execsql_test subquery-11.10 {
+  WITH c(a) AS (SELECT x'32' UNION SELECT ix FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT ix FROM t1 UNION SELECT x'32') SELECT affinity(a) FROM c;
+} {integer integer integer integer}
+do_execsql_test subquery-11.11 {
+  WITH c(a) AS (SELECT 4 UNION SELECT rx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT rx FROM t1 UNION SELECT 4) SELECT affinity(a) FROM c;
+} {real real real real}
+do_execsql_test subquery-11.12 {
+  WITH c(a) AS (SELECT '4' UNION SELECT rx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT rx FROM t1 UNION SELECT '4') SELECT affinity(a) FROM c;
+} {blob blob blob blob}
+do_execsql_test subquery-11.13 {
+  WITH c(a) AS (SELECT null UNION SELECT rx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT rx FROM t1 UNION SELECT null) SELECT affinity(a) FROM c;
+} {real real real real}
+do_execsql_test subquery-11.14 {
+  WITH c(a) AS (SELECT x'b4' UNION SELECT rx FROM t1) SELECT affinity(a) FROM c;
+  WITH c(a) AS (SELECT rx FROM t1 UNION SELECT x'b4') SELECT affinity(a) FROM c;
+} {real real real real}
 
 finish_test

test/view.test

@@ -801,4 +801,27 @@ ifcapable schema_pragmas {
   } { 0 a INT 0 {} 0 1 b BLOB 0 {} 0 }
 }
 
+#-----------------------------------------------------------------------
+# 2024-04-25   Trying to make type information on compound subqueries
+# more predictable and rational.
+#
+reset_db
+do_execsql_test view-31.1 {
+  CREATE TABLE x2(b TEXT);
+  CREATE TABLE x1(a TEXT);
+  INSERT INTO x1 VALUES('123');
+  -- Two queries get the same result even though the order of terms
+  -- in the CTE is reversed
+  WITH c(x) AS ( SELECT b FROM x2 UNION SELECT 123 )
+    SELECT count(*) FROM x1 WHERE a IN c; 
+  WITH c(x) AS ( SELECT 123 UNION SELECT b FROM x2 )
+    SELECT count(*) FROM x1 WHERE a IN c;
+} {0 0}
+do_execsql_test view-31.2 {
+  CREATE TABLE t3(a INTEGER, b TEXT);
+  INSERT INTO t3 VALUES(123, 123);
+  WITH s AS ( VALUES(123), (456) ) SELECT * FROM t3 WHERE b IN s;
+} {123 123}
+
+
 finish_test