PostgreSQL 8.3 Documentation....................................................................................215 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters avoid division by zero in a WHERE clause: SELECT ... WHERE x > 0 AND y/x > 1.5; But this is safe: SELECT ... WHERE CASE WHEN x > 0 THEN y/x > 1.5 ELSE false END; A CASE construct used in this fashion will0 码力 | 2143 页 | 4.58 MB | 1 年前3- PostgreSQL 8.3 Documentation....................................................................................203 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters avoid division by zero in a WHERE clause: SELECT ... WHERE x > 0 AND y/x > 1.5; But this is safe: SELECT ... WHERE CASE WHEN x > 0 THEN y/x > 1.5 ELSE false END; A CASE construct used in this fashion will0 码力 | 2015 页 | 4.54 MB | 1 年前3
- PostgreSQL 8.2 Documentation....................................................................................188 9.13.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters division by zero in a WHERE clause: SELECT ... WHERE x < > 0 AND y/x > 1.5; But this is safe: SELECT ... WHERE CASE WHEN x < > 0 THEN y/x > 1.5 ELSE false END; A CASE construct used in this fashion will0 码力 | 1748 页 | 13.12 MB | 1 年前3
- PostgreSQL 8.4 Documentation....................................................................................218 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). * is customarily not used for non- aggregate window functions. Aggregate window functions, unlike0 码力 | 2224 页 | 5.05 MB | 1 年前3
- PostgreSQL 8.4 Documentation....................................................................................232 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). * is customarily not used for non-aggregate window functions. Aggregate window functions, unlike normal0 码力 | 2371 页 | 5.09 MB | 1 年前3
- PostgreSQL 9.0 Documentation....................................................................................240 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). * is customarily not used for non-aggregate window functions. Aggregate window functions, unlike normal0 码力 | 2561 页 | 5.55 MB | 1 年前3
- PostgreSQL 9.0 Documentation....................................................................................224 9.16.2. COALESCE ............................................................................................... have defined a left unary operator 31 Chapter 4. SQL Syntax named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). * is customarily not used for non- aggregate window functions. Aggregate window functions, unlike0 码力 | 2401 页 | 5.50 MB | 1 年前3
- PostgreSQL 9.1.24 Documentation
....................................................................................233 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). * is customarily not used for non- aggregate window functions. Aggregate window functions, unlike0 码力 | 2667 页 | 6.57 MB | 1 年前3
- PostgreSQL 9.1 Documentation....................................................................................250 9.16.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). * is customarily not used for non-aggregate window functions. Aggregate window functions, unlike normal0 码力 | 2836 页 | 6.62 MB | 1 年前3
- PostgreSQL 9.3.25 Documentation....................................................................................252 9.17.2. COALESCE ............................................................................................... ambiguity. For example, if you have defined a left unary operator named @, you cannot write X*@Y; you must write X* @Y to ensure that PostgreSQL reads it as two operator names not one. 4.1.4. Special Characters parameter-less aggregate functions as window functions, for example count(*) OVER (PARTITION BY x ORDER BY y). The asterisk (*) is customarily not used for non-aggregate window functions. Aggregate window functions0 码力 | 3002 页 | 7.47 MB | 1 年前3
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