📅 最后修改于: 2021-01-04 04:58:13 🧑 作者: Mango
运算符是保留字或字符，主要用于SQLite语句的WHERE子句中，以执行操作，例如比较和算术运算。
运算符用于指定SQLite语句中的条件，并用作语句中多个条件的结合。
假设变量a持有10，变量b持有20，则将使用SQLite算术运算运算符-
| Operator | Description | Example |
|---|---|---|
| + (Addition) | Adds values on either side of the operator | a + b will give 30 |
| – (Subtraction) | Subtracts the right hand operand from the left hand operand | a – b will give -10 |
| * (Multiplication) | Multiplies values on either side of the operator | a * b will give 200 |
| / (Division) | Divides the left hand operand by the right hand operand | b / a will give 2 |
| % (Modulus) | Divides the left hand operand by the right hand operand and returns the remainder | b % a will give 0 |
假设变量保持10和变量b持有20，然后如下SQLite的运算符将用于
| Operator | Description | Example |
|---|---|---|
| == | Checks if the values of two operands are equal or not, if yes then the condition becomes true. | (a == b) is not true. |
| = | Checks if the values of two operands are equal or not, if yes then the condition becomes true. | (a = b) is not true. |
| != | Checks if the values of two operands are equal or not, if the values are not equal, then the condition becomes true. | (a != b) is true. |
| <> | Checks if the values of two operands are equal or not, if the values are not equal, then the condition becomes true. | (a <> b) is true. |
| > | Checks if the values of the left operand is greater than the value of the right operand, if yes then the condition becomes true. | (a > b) is not true. |
| < | Checks if the values of the left operand is less than the value of the right operand, if yes then the condition becomes true. | (a < b) is true. |
| >= | Checks if the value of the left operand is greater than or equal to the value of the right operand, if yes then the condition becomes true. | (a >= b) is not true. |
| <= | Checks if the value of the left operand is less than or equal to the value of the right operand, if yes then the condition becomes true. | (a <= b) is true. |
| !< | Checks if the value of the left operand is not less than the value of the right operand, if yes then the condition becomes true. | (a !< b) is false. |
| !> | Checks if the value of the left operand is not greater than the value of the right operand, if yes then the condition becomes true. | (a !> b) is true. |
这是SQLite中可用的所有逻辑运算符的列表。
| Sr.No. | Operator & Description |
|---|---|
| 1 |
AND The AND operator allows the existence of multiple conditions in an SQL statement’s WHERE clause. |
| 2 |
BETWEEN The BETWEEN operator is used to search for values that are within a set of values, given the minimum value and the maximum value. |
| 3 |
EXISTS The EXISTS operator is used to search for the presence of a row in a specified table that meets certain criteria. |
| 4 |
IN The IN operator is used to compare a value to a list of literal values that have been specified. |
| 5 |
NOT IN The negation of IN operator which is used to compare a value to a list of literal values that have been specified. |
| 6 |
LIKE The LIKE operator is used to compare a value to similar values using wildcard operators. |
| 7 |
GLOB The GLOB operator is used to compare a value to similar values using wildcard operators. Also, GLOB is case sensitive, unlike LIKE. |
| 8 |
NOT The NOT operator reverses the meaning of the logical operator with which it is used. Eg. NOT EXISTS, NOT BETWEEN, NOT IN, etc. This is negate operator. |
| 9 |
OR The OR operator is used to combine multiple conditions in an SQL statement’s WHERE clause. |
| 10 |
IS NULL The NULL operator is used to compare a value with a NULL value. |
| 11 |
IS The IS operator work like = |
| 12 |
IS NOT The IS operator work like != |
| 13 |
|| Adds two different strings and make new one. |
| 14 |
UNIQUE The UNIQUE operator searches every row of a specified table for uniqueness (no duplicates). |
按位运算符对位进行运算并执行逐位操作。以下是＆和|的真值表。
| p | q | p & q | p | q |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 |
| 1 | 1 | 1 | 1 |
| 1 | 0 | 0 | 1 |
假设A = 60;并且B = 13，然后采用二进制格式，它们将如下所示-
A = 0011 1100
B = 0000 1101
—————–
A＆B = 0000 1100
A | B = 0011 1101
〜A = 1100 0011
下表列出了SQLite语言支持的按位运算符。假设变量A保持60，变量B保持13，则-
| Operator | Description | Example |
|---|---|---|
| & | Binary AND Operator copies a bit to the result, if it exists in both operands. | (A & B) will give 12 which is 0000 1100 |
| | | Binary OR Operator copies a bit, if it exists in either operand. | (A | B) will give 61 which is 0011 1101 |
| ~ | Binary Ones Complement Operator is unary and has the effect of ‘flipping’ bits. | (~A ) will give -61 which is 1100 0011 in 2’s complement form due to a signed binary number |
| << | Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. | A << 2 will give 240 which is 1111 0000 |
| >> | Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand. | A >> 2 will give 15 which is 0000 1111 |