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0001 --
0002 -- Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
0003 --
0004 --
0005 -- CASE
0006 -- https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/sql/case.sql
0007 -- Test the CASE statement
0008 --
0009 -- This test file was converted from postgreSQL/case.sql.
0010 
0011 CREATE TABLE CASE_TBL (
0012   i integer,
0013   f double
0014 ) USING parquet;
0015 
0016 CREATE TABLE CASE2_TBL (
0017   i integer,
0018   j integer
0019 ) USING parquet;
0020 
0021 INSERT INTO CASE_TBL VALUES (1, 10.1);
0022 INSERT INTO CASE_TBL VALUES (2, 20.2);
0023 INSERT INTO CASE_TBL VALUES (3, -30.3);
0024 INSERT INTO CASE_TBL VALUES (4, NULL);
0025 
0026 INSERT INTO CASE2_TBL VALUES (1, -1);
0027 INSERT INTO CASE2_TBL VALUES (2, -2);
0028 INSERT INTO CASE2_TBL VALUES (3, -3);
0029 INSERT INTO CASE2_TBL VALUES (2, -4);
0030 INSERT INTO CASE2_TBL VALUES (1, NULL);
0031 INSERT INTO CASE2_TBL VALUES (NULL, -6);
0032 
0033 --
0034 -- Simplest examples without tables
0035 --
0036 
0037 SELECT '3' AS `One`,
0038   CASE
0039     WHEN udf(1 < 2) THEN 3
0040   END AS `Simple WHEN`;
0041 
0042 SELECT '<NULL>' AS `One`,
0043   CASE
0044     WHEN 1 > 2 THEN udf(3)
0045   END AS `Simple default`;
0046 
0047 SELECT '3' AS `One`,
0048   CASE
0049     WHEN udf(1) < 2 THEN udf(3)
0050     ELSE udf(4)
0051   END AS `Simple ELSE`;
0052 
0053 SELECT udf('4') AS `One`,
0054   CASE
0055     WHEN 1 > 2 THEN 3
0056     ELSE 4
0057   END AS `ELSE default`;
0058 
0059 SELECT udf('6') AS `One`,
0060   CASE
0061     WHEN udf(1 > 2) THEN 3
0062     WHEN udf(4) < 5 THEN 6
0063     ELSE 7
0064   END AS `Two WHEN with default`;
0065 
0066 SELECT '7' AS `None`,
0067   CASE WHEN rand() < udf(0) THEN 1
0068   END AS `NULL on no matches`;
0069 
0070 -- Constant-expression folding shouldn't evaluate unreachable subexpressions
0071 SELECT CASE WHEN udf(1=0) THEN 1/0 WHEN 1=1 THEN 1 ELSE 2/0 END;
0072 SELECT CASE 1 WHEN 0 THEN 1/udf(0) WHEN 1 THEN 1 ELSE 2/0 END;
0073 
0074 -- [SPARK-27923] PostgreSQL throws an exception but Spark SQL is NULL
0075 -- However we do not currently suppress folding of potentially
0076 -- reachable subexpressions
0077 SELECT CASE WHEN i > 100 THEN udf(1/0) ELSE udf(0) END FROM case_tbl;
0078 
0079 -- Test for cases involving untyped literals in test expression
0080 SELECT CASE 'a' WHEN 'a' THEN udf(1) ELSE udf(2) END;
0081 
0082 --
0083 -- Examples of targets involving tables
0084 --
0085 
0086 SELECT '' AS `Five`,
0087   CASE
0088     WHEN i >= 3 THEN i
0089   END AS `>= 3 or Null`
0090   FROM CASE_TBL;
0091 
0092 SELECT '' AS `Five`,
0093   CASE WHEN i >= 3 THEN (i + i)
0094        ELSE i
0095   END AS `Simplest Math`
0096   FROM CASE_TBL;
0097 
0098 SELECT '' AS `Five`, i AS `Value`,
0099   CASE WHEN (i < 0) THEN 'small'
0100        WHEN (i = 0) THEN 'zero'
0101        WHEN (i = 1) THEN 'one'
0102        WHEN (i = 2) THEN 'two'
0103        ELSE 'big'
0104   END AS `Category`
0105   FROM CASE_TBL;
0106 
0107 SELECT '' AS `Five`,
0108   CASE WHEN ((i < 0) or (i < 0)) THEN 'small'
0109        WHEN ((i = 0) or (i = 0)) THEN 'zero'
0110        WHEN ((i = 1) or (i = 1)) THEN 'one'
0111        WHEN ((i = 2) or (i = 2)) THEN 'two'
0112        ELSE 'big'
0113   END AS `Category`
0114   FROM CASE_TBL;
0115 
0116 --
0117 -- Examples of qualifications involving tables
0118 --
0119 
0120 --
0121 -- NULLIF() and COALESCE()
0122 -- Shorthand forms for typical CASE constructs
0123 --  defined in the SQL standard.
0124 --
0125 
0126 SELECT * FROM CASE_TBL WHERE udf(COALESCE(f,i)) = 4;
0127 
0128 SELECT * FROM CASE_TBL WHERE udf(NULLIF(f,i)) = 2;
0129 
0130 SELECT udf(COALESCE(a.f, b.i, b.j))
0131   FROM CASE_TBL a, CASE2_TBL b;
0132 
0133 SELECT *
0134    FROM CASE_TBL a, CASE2_TBL b
0135    WHERE udf(COALESCE(a.f, b.i, b.j)) = 2;
0136 
0137 SELECT udf('') AS Five, NULLIF(a.i,b.i) AS `NULLIF(a.i,b.i)`,
0138   NULLIF(b.i, 4) AS `NULLIF(b.i,4)`
0139   FROM CASE_TBL a, CASE2_TBL b;
0140 
0141 SELECT '' AS `Two`, *
0142   FROM CASE_TBL a, CASE2_TBL b
0143   WHERE udf(COALESCE(f,b.i) = 2);
0144 
0145 -- We don't support update now.
0146 --
0147 -- Examples of updates involving tables
0148 --
0149 
0150 -- UPDATE CASE_TBL
0151 --   SET i = CASE WHEN i >= 3 THEN (- i)
0152 --                 ELSE (2 * i) END;
0153 
0154 -- SELECT * FROM CASE_TBL;
0155 
0156 -- UPDATE CASE_TBL
0157 --   SET i = CASE WHEN i >= 2 THEN (2 * i)
0158 --                 ELSE (3 * i) END;
0159 
0160 -- SELECT * FROM CASE_TBL;
0161 
0162 -- UPDATE CASE_TBL
0163 --   SET i = CASE WHEN b.i >= 2 THEN (2 * j)
0164 --                 ELSE (3 * j) END
0165 --   FROM CASE2_TBL b
0166 --   WHERE j = -CASE_TBL.i;
0167 
0168 -- SELECT * FROM CASE_TBL;
0169 
0170 --
0171 -- Nested CASE expressions
0172 --
0173 
0174 -- This test exercises a bug caused by aliasing econtext->caseValue_isNull
0175 -- with the isNull argument of the inner CASE's CaseExpr evaluation.  After
0176 -- evaluating the vol(null) expression in the inner CASE's second WHEN-clause,
0177 -- the isNull flag for the case test value incorrectly became true, causing
0178 -- the third WHEN-clause not to match.  The volatile function calls are needed
0179 -- to prevent constant-folding in the planner, which would hide the bug.
0180 
0181 -- Wrap this in a single transaction so the transient '=' operator doesn't
0182 -- cause problems in concurrent sessions
0183 -- BEGIN;
0184 
0185 -- CREATE FUNCTION vol(text) returns text as
0186 --   'begin return $1; end' language plpgsql volatile;
0187 
0188 SELECT CASE
0189   (CASE vol('bar')
0190     WHEN udf('foo') THEN 'it was foo!'
0191     WHEN udf(vol(null)) THEN 'null input'
0192     WHEN 'bar' THEN 'it was bar!' END
0193   )
0194   WHEN udf('it was foo!') THEN 'foo recognized'
0195   WHEN 'it was bar!' THEN udf('bar recognized')
0196   ELSE 'unrecognized' END AS col;
0197 
0198 -- We don't support the features below:
0199 -- 1. CREATE DOMAIN ...
0200 -- 2. CREATE OPERATOR ...
0201 -- 3. CREATE TYPE ...
0202 
0203 -- In this case, we can't inline the SQL function without confusing things.
0204 -- CREATE DOMAIN foodomain AS text;
0205 
0206 -- CREATE FUNCTION volfoo(text) returns foodomain as
0207 --   'begin return $1::foodomain; end' language plpgsql volatile;
0208 
0209 -- CREATE FUNCTION inline_eq(foodomain, foodomain) returns boolean as
0210 --   'SELECT CASE $2::text WHEN $1::text THEN true ELSE false END' language sql;
0211 
0212 -- CREATE OPERATOR = (procedure = inline_eq,
0213 --                    leftarg = foodomain, rightarg = foodomain);
0214 
0215 -- SELECT CASE volfoo('bar') WHEN 'foo'::foodomain THEN 'is foo' ELSE 'is not foo' END;
0216 
0217 -- ROLLBACK;
0218 
0219 -- Test multiple evaluation of a CASE arg that is a read/write object (#14472)
0220 -- Wrap this in a single transaction so the transient '=' operator doesn't
0221 -- cause problems in concurrent sessions
0222 -- BEGIN;
0223 
0224 -- CREATE DOMAIN arrdomain AS int[];
0225 
0226 -- CREATE FUNCTION make_ad(int,int) returns arrdomain as
0227 --   'declare x arrdomain;
0228 --    begin
0229 --      x := array[$1,$2];
0230 --      return x;
0231 --    end' language plpgsql volatile;
0232 
0233 -- CREATE FUNCTION ad_eq(arrdomain, arrdomain) returns boolean as
0234 --   'begin return array_eq($1, $2); end' language plpgsql;
0235 
0236 -- CREATE OPERATOR = (procedure = ad_eq,
0237 --                    leftarg = arrdomain, rightarg = arrdomain);
0238 
0239 -- SELECT CASE make_ad(1,2)
0240 --   WHEN array[2,4]::arrdomain THEN 'wrong'
0241 --   WHEN array[2,5]::arrdomain THEN 'still wrong'
0242 --   WHEN array[1,2]::arrdomain THEN 'right'
0243 --   END;
0244 
0245 -- ROLLBACK;
0246 
0247 -- Test interaction of CASE with ArrayCoerceExpr (bug #15471)
0248 -- BEGIN;
0249 
0250 -- CREATE TYPE casetestenum AS ENUM ('e', 'f', 'g');
0251 
0252 -- SELECT
0253 --   CASE 'foo'::text
0254 --     WHEN 'foo' THEN ARRAY['a', 'b', 'c', 'd'] || enum_range(NULL::casetestenum)::text[]
0255 --     ELSE ARRAY['x', 'y']
0256 --     END;
0257 
0258 -- ROLLBACK;
0259 
0260 --
0261 -- Clean up
0262 --
0263 
0264 DROP TABLE CASE_TBL;
0265 DROP TABLE CASE2_TBL;