Implement the IIF(x,y,z) SQL function that is short-hand for

"CASE WHEN x THEN y ELSE z END".  For compatibility with SQL Server.

FossilOrigin-Name: fce173cd211b15867369b6a54fad48168352fc83981a722ce98e57299b88608a

manifest

@@ -1,5 +1,5 @@
-C Remove\sunused\sconstant\sSQLITE_FUNC_COALESCE.
+C Implement\sthe\sIIF(x,y,z)\sSQL\sfunction\sthat\sis\sshort-hand\sfor\n"CASE\sWHEN\sx\sTHEN\sy\sELSE\sz\sEND".\s\sFor\scompatibility\swith\sSQL\sServer.
-D 2020-05-13T17:26:38.564
+D 2020-05-13T18:03:34.396
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -485,10 +485,10 @@ F src/date.c b29b349d277e3d579dcc295b24c0a2caed83fd8f090a9f7cbe6070c0fd662384
 F src/dbpage.c 8a01e865bf8bc6d7b1844b4314443a6436c07c3efe1d488ed89e81719047833a
 F src/dbstat.c 793deaf88a0904f88285d93d6713c636d55ede0ffd9f08d10f4ea825531d367f
 F src/delete.c 88047c8e59878c920fce14582bc1dde4d81157d1ca5ffdf36c2907e6d41996c4
-F src/expr.c 2918cac044a96d534d2f51bd121e913afda57314b8c5b00eb6bc1cf8999a7dea
+F src/expr.c 8eed44d9de8a3b0fe1c9809bb75a02b65488774c8ba8685512d8f63adade18e5
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 4b575423b0a5d4898b1a7868ce985cf1a8ad91c741c9abbb108ff02536d20f41
-F src/func.c 3065eb46cd973dedb5159834947125a1be7e84c3f2d838ea0d5999ec59865e66
+F src/func.c 4780623a0c67f9241d4d5360a7d612826cfb22b825d95de9dce959c43c09ff47
 F src/global.c 79a988b56b06ce2d08ebefe1d35da9aa25b3851faa47ea5233361c4827185a64
 F src/hash.c 8d7dda241d0ebdafb6ffdeda3149a412d7df75102cecfc1021c98d6219823b19
 F src/hash.h 9d56a9079d523b648774c1784b74b89bd93fac7b365210157482e4319a468f38
@@ -538,7 +538,7 @@ F src/shell.c.in cf2d24f54412c06e5fb34af7fabc748651125e1dceac29b740e91f06d23447b
 F src/sqlite.h.in a42bae930f462294801f24468dd56832b09de01072a26dc0df60ddc3c5602210
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 2d1af80082edffd71c6f96f70ad1ce6a4fb46615ad10291fc77fe0dea9ff0197
-F src/sqliteInt.h 1a44887a8cea894d771114ad9d47527fd0a360dedc0392df834b425c3c8e227e
+F src/sqliteInt.h 610ea213d892d1dce31445be864115dab6909631d224e3420b40b46fbc21e2b3
 F src/sqliteLimit.h 95cb8479ca459496d9c1c6a9f76b38aee12203a56ce1092fe13e50ae2454c032
 F src/status.c 9ff2210207c6c3b4d9631a8241a7d45ab1b26a0e9c84cb07a9b5ce2de9a3b278
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -835,7 +835,7 @@ F test/e_createtable.test ea27082d6f84df61e1d9e383f3fd79220418856a4a8afc41af75d4
 F test/e_delete.test ab39084f26ae1f033c940b70ebdbbd523dc4962e
 F test/e_droptrigger.test 3cd080807622c13e5bbb61fc9a57bd7754da2412
 F test/e_dropview.test 74e405df7fa0f762e0c9445b166fe03955856532e2bb234c372f7c51228d75e7
-F test/e_expr.test 328d2d7c84f8e53e942a13eac771b337bcdfcf4c3569324001868b5639f3c857
+F test/e_expr.test 0d4e5bb50e60ee58aaf0c1184b4ee65cd3351e9aa54ca6568cef075288e58088
 F test/e_fkey.test 2febb2084aef9b0186782421c07bc9d377abf067c9cb4efd49d9647ae31f5afe
 F test/e_fts3.test 17ba7c373aba4d4f5696ba147ee23fd1a1ef70782af050e03e262ca187c5ee07
 F test/e_insert.test f02f7f17852b2163732c6611d193f84fc67bc641fb4882c77a464076e5eba80e
@@ -1864,7 +1864,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P fda57d4d2f1499c861d43026aa9362d1a30d67c9c002ebf5b0cdc25251537fbb
+P a116b20f863e9732cd08fbfbb1aa48204a17d611c9c1edde85dcf59310bde782
-R bd6cc4135d37a123d6913c8ebb546f8c
+R f70dac47e4a001bdb43fd3a204ed3565
 U drh
-Z 4c9f597f730cc29a882d279a7e4f39c6
+Z 216cd8b87e5791c27226341eec7b12c9

manifest.uuid

@@ -1 +1 @@
-a116b20f863e9732cd08fbfbb1aa48204a17d611c9c1edde85dcf59310bde782
+fce173cd211b15867369b6a54fad48168352fc83981a722ce98e57299b88608a

src/expr.c

@@ -3700,6 +3700,13 @@ static int exprCodeInlineFunction(
       sqlite3VdbeResolveLabel(v, endCoalesce);
       break;
     }
+    case INLINEFUNC_iif: {
+      Expr caseExpr;
+      memset(&caseExpr, 0, sizeof(caseExpr));
+      caseExpr.op = TK_CASE;
+      caseExpr.x.pList = pFarg;
+      return sqlite3ExprCodeTarget(pParse, &caseExpr, target);
+    }
 
     default: {   
       /* The UNLIKELY() function is a no-op.  The result is the value

src/func.c

@@ -2021,6 +2021,7 @@ void sqlite3RegisterBuiltinFunctions(void){
     FUNCTION(coalesce,           1, 0, 0, 0                ),
     FUNCTION(coalesce,           0, 0, 0, 0                ),
     INLINE_FUNC(coalesce,       -1, INLINEFUNC_coalesce, 0 ),
+    INLINE_FUNC(iif,             3, INLINEFUNC_iif,      0 ),
   };
 #ifndef SQLITE_OMIT_ALTERTABLE
   sqlite3AlterFunctions();

src/sqliteInt.h

@@ -1785,6 +1785,7 @@ struct FuncDestructor {
 #define INLINEFUNC_expr_implies_expr    2
 #define INLINEFUNC_expr_compare         3      
 #define INLINEFUNC_affinity             4
+#define INLINEFUNC_iif                  5
 #define INLINEFUNC_unlikely            99  /* Default case */
 
 /*

test/e_expr.test

@@ -1235,11 +1235,11 @@ db nullvalue {}
 # evaluating WHEN terms.
 #
 do_execsql_test e_expr-21.4.1 {
-  SELECT CASE WHEN NULL THEN 'A' WHEN 1 THEN 'B' END
+  SELECT CASE WHEN NULL THEN 'A' WHEN 1 THEN 'B' END, iif(NULL,8,99);
-} {B}
+} {B 99}
 do_execsql_test e_expr-21.4.2 {
-  SELECT CASE WHEN 0 THEN 'A' WHEN NULL THEN 'B' ELSE 'C' END
+  SELECT CASE WHEN 0 THEN 'A' WHEN NULL THEN 'B' ELSE 'C' END, iif(0,8,99);
-} {C}
+} {C 99}
 
 # EVIDENCE-OF: R-38620-19499 In a CASE with a base expression, the base
 # expression is evaluated just once and the result is compared against
@@ -1952,39 +1952,39 @@ foreach {tn expr} {
 # 'english' and '0' are all considered to be false.
 #
 do_execsql_test e_expr-37.1 {
-   SELECT CASE WHEN NULL THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN NULL THEN 'true' ELSE 'false' END, iif(NULL,'true','false');
-} {false}
+} {false false}
 do_execsql_test e_expr-37.2 {
-   SELECT CASE WHEN 0.0 THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN 0.0 THEN 'true' ELSE 'false' END, iif(0.0,'true','false');
-} {false}
+} {false false}
 do_execsql_test e_expr-37.3 {
-   SELECT CASE WHEN 0 THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN 0 THEN 'true' ELSE 'false' END, iif(0,'true','false');
-} {false}
+} {false false}
 do_execsql_test e_expr-37.4 {
-   SELECT CASE WHEN 'engligh' THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN 'engligh' THEN 'true' ELSE 'false' END, iif('engligh','true','false');
-} {false}
+} {false false}
 do_execsql_test e_expr-37.5 {
-   SELECT CASE WHEN '0' THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN '0' THEN 'true' ELSE 'false' END, iif('0','true','false');
-} {false}
+} {false false}
 
 # EVIDENCE-OF: R-55532-10108 Values 1, 1.0, 0.1, -0.1 and '1english' are
 # considered to be true.
 #
 do_execsql_test e_expr-37.6 {
-   SELECT CASE WHEN 1 THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN 1 THEN 'true' ELSE 'false' END, iif(1,'true','false');
-} {true}
+} {true true}
 do_execsql_test e_expr-37.7 {
-   SELECT CASE WHEN 1.0 THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN 1.0 THEN 'true' ELSE 'false' END, iif(1.0,'true','false');
-} {true}
+} {true true}
 do_execsql_test e_expr-37.8 {
-   SELECT CASE WHEN 0.1 THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN 0.1 THEN 'true' ELSE 'false' END, iif(0.1,'true','false');
-} {true}
+} {true true}
 do_execsql_test e_expr-37.9 {
-   SELECT CASE WHEN -0.1 THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN -0.1 THEN 'true' ELSE 'false' END, iif(-0.1,'true','false');
-} {true}
+} {true true}
 do_execsql_test e_expr-37.10 {
-   SELECT CASE WHEN '1english' THEN 'true' ELSE 'false' END;
+   SELECT CASE WHEN '1english' THEN 'true' ELSE 'false' END, iif('1engl','true','false');
-} {true}
+} {true true}
 
 
 finish_test