tsql nullif

http://blog.csdn.net/baoshan/article/details/2907602 COALESCE () Usage Select COALESCE (null,null, ' 1 ', ' 2 ') returns 1 Action returns the first NON-EMPTY expression in its argument. IsNull () Usage Select isnull (null,0) returns 0 Action encountered null return specified value Nullif () Usage nullif (' AA ', ' AA ') returns NULL, NULLIF (1,2) returns 1 Ac

Tags: SQ Express description Type First expression res select ValISNULL (Check_expression, Replacement_value) The check_expression and Replacement_value data types must be the same, and if Check_expression is NULL, Replacement_value is returned if Check_expression is not NULL, the check_expression is returned Nullif (expression, expression) If two expressions are equal, returns NULL, which is the data type of the first expression, and if two expressi

Tags: code SSI parameter using SQL coalesce otherwise log class nullif function Nullif (expression1,expression2): Given two parameters Expression1 and Expression2, if two parameters are equal, NULL is returned, otherwise the first argument is returned. Equivalent to: case when Expression1=Expression2 then NULL ELSE Expression1. For example, select Nullif (1,1) re

Common Oracle functions: nvl/nullif/case when/wm_concat/replace 1. nvl function nvl converts a null value to an actual value. The data type can be date, number, character, and data type must match: nvl (commision, 0) nvl (hiredate, '01-JAN-87 ') nvl (job_id, 'no manager') nvl (to_char (job_id), 'no manager') nvl can convert any data type, however, the returned value of the converted data type must be of the expr type of the first parameter nvl (expr1,

The two functions nullif and isnull in SQL Server are described as follows: Nullif: two parameters are required. Example: nullif (A, B)Note: If a and B are equal, null is returned. If not, A is returned.Select nullif ('eqeqweqw', '1'). The result is eqeqweqwe.Select nullif

Label:Today used in the MySQL IsNull only found him and MSSQL in a little difference, now briefly summarize: The usage of isnull,ifnull,nullif in MySQL is as follows: Usage of IsNull (expr):If expr is null, then the return value of IsNull () is 1, otherwise the return value is 0.Mysql> Select IsNull (+);0Mysql> Select IsNull (1/0);1The comparison of NULL values using = is usually wrong.The IsNull () function has some of the same characteristics as the

functions are general functions. Mainly: NVL,NVL2,NULLIF,COALESCE, these functions can be used on all types.The following is a brief introduction to the use of several functions.Before you introduce this, you have to understand what a null value in Oracle is NULL1.NVL functionThe format of the NVL function is as follows: NVL (EXPR1,EXPR2)The meaning is: if the first parameter of Oracle is empty then the value of the second parameter is displayed, and

Tips for using functions in Oracle (2)-The NULLIF function provides the abbreviated CASE expression through a comparison expression. Syntax NULLIF (expression-1, expression-2) the expression to be compared with expression-1. Expression-2: The expression to be compared. Use NULLIF to compare the values of two expressions. If the value of the first expression is eq

In the spelling of the SQL statement to do a select out of the field to sum the query, search the Internet, get some inspiration, here to write. Let's begin by introducing the function you use: 1, Nullif (ORACLE and SQL Server use the same): Usage: Nullif (expression1 , expression2), Description: If two expressions are not equal, NULLIF returns the value of the

IsNull is to determine if NULLAnd Nullif is to change the value to null.Coalesce is replacing null with something else.SELECT Employee_id,first_name,last_name,nullif (sales_quota,-1) as QUOTAFrom Employeesis to turn 1 into NULL.COALESCE (expression 1, expression 2,.... Expression N)From the front to the back, who is not NULL to show whoSelect Employee_id,first_name,last_name,COALESCE (Appt_quota, (Select Mi

Nvl (expr1, expr2)Nvl2 (expr1, expr2, expr3)Nullif (expr1, expr2)Coalesce (expr1,..., exprn)Decode -------- NvlNvl (commission_pct, 0)If the first parameter is null, the second parameter is returned.If the first parameter is not null, the first parameter is returned. Typical Example: Calculate the annual salary (salary + Commission)Select last_name, salary, nvl (commission_pct, 0 ),(Salary * 12) + (salary * 12 * nvl (commission_pct, 0) annual_salaryFr

Reference and http://blog.csdn.net/xingyu0806/article/details/52080962Ifnull (EXPR1,EXPR2)If EXPR1 is not NULL, the return value of Ifnull () is expr1; Otherwise its return value is EXPR2 (numeric or string). The return value of Ifnull () is either a number or a string.Usage of ISNULL (expr)If expr is null, then the return value of IsNull () is 1, otherwise the return value is 0.Nullif (EXPR1,EXPR2) usageIf Expr1 = EXPR2 is established, then the retur

NULL refers to a null value, or an illegal value.1, NVL (expr1, expr2) functionEXPR1 is null, returns EXPR2, is not NULL, returns EXPR1. Note that the two types should be consistentEg:select NVL (column,0) from DUAL--column value is null, it is displayed as 02, NVL2 (Expr1, EXPR2, EXPR3)EXPR1 is not NULL, returns EXPR2, or null, returning EXPR3. EXPR3 will be converted to EXPR2 type if the EXPR2 and EXPR3 types are differentEg:select NVL2 (column,1,0) The value of the from DUAL--column is not NU

I recently used some functions in mysql, some of which were first encountered, so I recorded that: 1 isnull (expr) usage: expr is null, then isnull () returns 20540; 1, otherwise, 20540 is returned; 0 is returned. 2 IFNULL (expr1, expr2) usage: If you recently used some functions in mysql, some of them are first encountered, so record them: 1. isnull (expr)Usage: if expr is null, the return value of isnull () is 1; otherwise, the return value is 0. 2. IFNULL (expr1, expr2) Usage: if exp

PLSQL _ basic series 6_determine the operation NVL/NULLIF/COALESCE/NVL2, plsqlnvl BaoXinjian I. Summary The following functions are applicable to any data type and use null values:NVL (expr1, expr2)NVL2 (expr1, expr2, expr3)NULLIF (expr1, expr2)COALESCE (expr1, expr2,..., exprn) Ii. Case study-NVL 1. The NVL function format is as follows: NVL (expr1, expr2) 2. Meaning: if the first oracle parameter is b

SQL Server has two parameters. Syntax:ISNULL (check_expression, replacement_value) The check_expression and replacement_value data types must be consistent.If check_expression is NULL, replacement_value is returned.If check_expression is not NULL, check_expression is returned. NULLIF is used to check two expressions. Syntax: NULLIF (expression, expression) If two expressions are equal, NULL is returned, whi

OracleDBNVL, NVL2, NULLIF, COALESCE Functions Oracle db nvl, NVL2, NULLIF, COALESCE Functions Regular Functions The following functions are applicable to any data type and use null values: • NVL (expr1, expr2) • NVL2 (expr1, expr2, expr3) • NULLIF (expr1, expr2) • COALESCE (expr1, expr2,..., exprn) The following functions are applicable to any data typ

Usage of IFNULL, NULLIF, and ISNULL in MySql bitsCN.com In MySql, IFNULL, NULLIF, and ISNULL are used in MySql to find that isnull in mysql is a little different from that in MSSQL. now, let's briefly summarize: isnull and ifnull in MySql, the usage of nullif is as follows: isnull (expr): if expr is null, the return value of isnull () is 1; otherwise, the return

Description of IFNULL, NULLIF, and ISNULL usage in MySql, ifnullnullif I used isnull in MySql today to find that it is a little different from MSSQL. Now, let's briefly summarize: In mysql, isnull, ifnull, and nullif are used as follows: Isnull (expr) usage: If expr is null, the return value of isnull () is 1; otherwise, the return value is 0. mysql> select isnull(1+1);-> 0mysql> select isnull(1/0);-> 1 The

2014-12-08 BaoxinjianI. Summary The following functions are available for any data type and are suitable for use with null values:NVL (EXPR1, EXPR2)NVL2 (Expr1, EXPR2, EXPR3)Nullif (EXPR1, EXPR2)COALESCE (EXPR1, expr2, ..., exprn)Second, case-NVL 1. The format of the NVL function is as follows: NVL (EXPR1,EXPR2)2. The meaning is: if the first parameter of Oracle is empty then the value of the second parameter is displayed, and if the value