From: drh <>
Date: Fri, 8 Apr 2022 15:11:10 +0000 (+0000)
Subject: Improved explanation and commentary on the sqlite3JoinType() routine.  One
X-Git-Tag: version-3.39.0~224
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=81a23623d8790fca64f6e6551f59a2d4694dbf75;p=thirdparty%2Fsqlite.git

Improved explanation and commentary on the sqlite3JoinType() routine.  One
of the error messages changes slightly, but besides that everything works
the same.

FossilOrigin-Name: 48f2e5a1fbaa8ceb32e08066766be74233b0c67ab430bbf7adfdff42cdb7b8ec
---

diff --git a/manifest b/manifest
index 9e29deaa06..a2472f06dc 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\stwo\sunreachable\sbranches\sintroduced\sby\sthe\srecent\nsqlite3TriggersExist()\soptimization.
-D 2022-04-07T20:45:38.697
+C Improved\sexplanation\sand\scommentary\son\sthe\ssqlite3JoinType()\sroutine.\s\sOne\nof\sthe\serror\smessages\schanges\sslightly,\sbut\sbesides\sthat\severything\sworks\nthe\ssame.
+D 2022-04-08T15:11:10.072
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -552,7 +552,7 @@ F src/printf.c 05d8dfd2018bc4fc3ddb8b37eb97ccef7abf985643fa1caebdcf2916ca90fa32
 F src/random.c 097dc8b31b8fba5a9aca1697aeb9fd82078ec91be734c16bffda620ced7ab83c
 F src/resolve.c 18d99e7146852d6064559561769fcca0743eb32b14a97da6dbed373a30ee0e76
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c d6c04eb93395024af80f61a8c278a33c2a0333aeb7d57bb6aa737a6f1c4af4b8
+F src/select.c 7c106b3f36d483242b0a9c696614cd53d6f29e1ac81da6a3f0e9ea92f4211cc3
 F src/shell.c.in 1a8fbf932ecd582b1a5f66c1e8294f92c30d954616f5c7cc54c9623fcdbb028d
 F src/sqlite.h.in 2a35f62185eb5e7ecc64a2f68442b538ce9be74f80f28a00abc24837edcf1c17
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -1945,8 +1945,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P c2965fea9df7076b235d3eadaf84f0a36242476d0329030b0e57557b66e2540c
-R 07d0b0c26e9cd2798bbb00ddbafc6a3b
+P 1b5475d212cf9de0bff69eee8c607b4fcd8e04bf4df72171429e7609c4153951
+R 931142dc24337bfedaa0369d45a2c00c
 U drh
-Z 93237070ff101cf9292ceb1ee884c28a
+Z 277112caa7eb0641987ae3d1eca17748
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 55edbcf9bb..b27079fd83 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-1b5475d212cf9de0bff69eee8c607b4fcd8e04bf4df72171429e7609c4153951
\ No newline at end of file
+48f2e5a1fbaa8ceb32e08066766be74233b0c67ab430bbf7adfdff42cdb7b8ec
\ No newline at end of file
diff --git a/src/select.c b/src/select.c
index 989446af61..7ac23bd388 100644
--- a/src/select.c
+++ b/src/select.c
@@ -204,6 +204,52 @@ static Select *findRightmost(Select *p){
 **
 ** If an illegal or unsupported join type is seen, then still return
 ** a join type, but put an error in the pParse structure.
+**
+** These are the valid join types:
+**
+**
+**      pA       pB       pC               Return Value
+**     -------  -----    -----             ------------
+**     CROSS      -        -                 JT_CROSS
+**     INNER      -        -                 JT_INNER
+**     LEFT       -        -                 JT_LEFT|JT_OUTER
+**     LEFT     OUTER      -                 JT_LEFT|JT_OUTER
+**     RIGHT      -        -                 JT_RIGHT|JT_OUTER
+**     RIGHT    OUTER      -                 JT_RIGHT|JT_OUTER
+**     FULL       -        -                 JT_LEFT|JT_RIGHT|JT_OUTER
+**     FULL     OUTER      -                 JT_LEFT|JT_RIGHT|JT_OUTER
+**     NATURAL  INNER      -                 JT_NATURAL|JT_INNER
+**     NATURAL  LEFT       -                 JT_NATURAL|JT_LEFT|JT_OUTER
+**     NATURAL  LEFT     OUTER               JT_NATURAL|JT_LEFT|JT_OUTER
+**     NATURAL  RIGHT      -                 JT_NATURAL|JT_RIGHT|JT_OUTER
+**     NATURAL  RIGHT    OUTER               JT_NATURAL|JT_RIGHT|JT_OUTER
+**     NATURAL  FULL       -                 JT_NATURAL|JT_LEFT|JT_RIGHT
+**     NATURAL  FULL     OUTER               JT_NATRUAL|JT_LEFT|JT_RIGHT
+**
+** To preserve historical compatibly, SQLite also accepts a variety 
+** of other non-standard and in many cases non-sensical join types.
+** This routine makes as much sense at it can from the nonsense join
+** type and returns a result.  Examples of accepted nonsense join types
+** include but are not limited to:
+**
+**          INNER CROSS JOIN        ->   same as JOIN
+**          NATURAL CROSS JOIN      ->   same as NATURAL JOIN
+**          OUTER LEFT JOIN         ->   same as LEFT JOIN
+**          LEFT NATURAL JOIN       ->   same as NATURAL LEFT JOIN
+**          LEFT RIGHT JOIN         ->   same as FULL JOIN
+**          RIGHT OUTER FULL JOIN   ->   same as FULL JOIN
+**          CROSS CROSS CROSS JOIN  ->   same as JOIN
+**
+** The only restrictions on the join type name are:
+**
+**    *   "INNER" cannot appear together with "OUTER", "LEFT", "RIGHT",
+**        or "FULL".
+**
+**    *   "CROSS" cannot appear together with "OUTER", "LEFT", "RIGHT,
+**        or "FULL".
+**
+**    *   If "OUTER" is present then there must also be one of
+**        "LEFT", "RIGHT", or "FULL"
 */
 int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
   int jointype = 0;
@@ -216,13 +262,13 @@ int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
     u8 nChar;    /* Length of the keyword in characters */
     u8 code;     /* Join type mask */
   } aKeyword[] = {
-    /* natural */ { 0,  7, JT_NATURAL                },
-    /* left    */ { 6,  4, JT_LEFT|JT_OUTER          },
-    /* outer   */ { 10, 5, JT_OUTER                  },
-    /* right   */ { 14, 5, JT_RIGHT|JT_OUTER         },
-    /* full    */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
-    /* inner   */ { 23, 5, JT_INNER                  },
-    /* cross   */ { 28, 5, JT_INNER|JT_CROSS         },
+    /* (0) natural */ { 0,  7, JT_NATURAL                },
+    /* (1) left    */ { 6,  4, JT_LEFT|JT_OUTER          },
+    /* (2) outer   */ { 10, 5, JT_OUTER                  },
+    /* (3) right   */ { 14, 5, JT_RIGHT|JT_OUTER         },
+    /* (4) full    */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
+    /* (5) inner   */ { 23, 5, JT_INNER                  },
+    /* (6) cross   */ { 28, 5, JT_INNER|JT_CROSS         },
   };
   int i, j;
   apAll[0] = pA;
@@ -245,16 +291,17 @@ int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
   }
   if(
      (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
-     (jointype & JT_ERROR)!=0
+     (jointype & JT_ERROR)!=0 ||
+     (jointype & (JT_OUTER|JT_LEFT|JT_RIGHT))==JT_OUTER
   ){
-    const char *zSp = " ";
-    assert( pB!=0 );
-    if( pC==0 ){ zSp++; }
+    const char *zSp1 = " ";
+    const char *zSp2 = " ";
+    if( pB==0 ){ zSp1++; }
+    if( pC==0 ){ zSp2++; }
     sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
-       "%T %T%s%T", pA, pB, zSp, pC);
+       "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
     jointype = JT_INNER;
-  }else if( (jointype & JT_OUTER)!=0 
-         && (jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ){
+  }else if( (jointype & JT_RIGHT)!=0 ){
     sqlite3ErrorMsg(pParse, 
       "RIGHT and FULL OUTER JOINs are not currently supported");
     jointype = JT_INNER;