How to use SELECT parameters assignments in MySQL queries?
I've been migrating MSSQL DB into MySQL and facing a syntax I cannot find anywhere and need this help.
All "MySQL parameters" question deals with "select * from mytable where id = @id" but I'm looking for the below syntax:
SELECT @MyParam = MyValue FROM MyTable
While "SELECT MyValue FROM MyTable" returns values, running the above @MyParam query returns NULLs.
From previous answers I see that as opposed to MSSQL, in MySQL the parameters aren't predefined with any datatype.
What am I missing here?
THX
mysql parameters
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
add a comment |
I've been migrating MSSQL DB into MySQL and facing a syntax I cannot find anywhere and need this help.
All "MySQL parameters" question deals with "select * from mytable where id = @id" but I'm looking for the below syntax:
SELECT @MyParam = MyValue FROM MyTable
While "SELECT MyValue FROM MyTable" returns values, running the above @MyParam query returns NULLs.
From previous answers I see that as opposed to MSSQL, in MySQL the parameters aren't predefined with any datatype.
What am I missing here?
THX
mysql parameters
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
add a comment |
I've been migrating MSSQL DB into MySQL and facing a syntax I cannot find anywhere and need this help.
All "MySQL parameters" question deals with "select * from mytable where id = @id" but I'm looking for the below syntax:
SELECT @MyParam = MyValue FROM MyTable
While "SELECT MyValue FROM MyTable" returns values, running the above @MyParam query returns NULLs.
From previous answers I see that as opposed to MSSQL, in MySQL the parameters aren't predefined with any datatype.
What am I missing here?
THX
mysql parameters
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
I've been migrating MSSQL DB into MySQL and facing a syntax I cannot find anywhere and need this help.
All "MySQL parameters" question deals with "select * from mytable where id = @id" but I'm looking for the below syntax:
SELECT @MyParam = MyValue FROM MyTable
While "SELECT MyValue FROM MyTable" returns values, running the above @MyParam query returns NULLs.
From previous answers I see that as opposed to MSSQL, in MySQL the parameters aren't predefined with any datatype.
What am I missing here?
THX
mysql parameters
mysql parameters
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
edited Nov 13 '18 at 10:51
Rory McCrossan
241k29206245
241k29206245
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
asked Nov 13 '18 at 10:45
Dave GahanDave Gahan
1169
1169
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
You need to use := operator instead of =, when you are assigning value to a user-defined variable in the SELECT clause. Former is assignment operator; while the latter is comparison operator.
SELECT @MyParam := MyValue FROM MyTable
However, if you are using SET clause, then you can use either = or :=. From docs:
For SET, either = or := can be used as the assignment operator.
More from the docs:
When making an assignment in this way (using
SELECT), you must use
:= as the assignment operator; = is treated as the comparison operator
in statements other than SET.
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
1
The:=format withSELCECTwill cause extra result set from the procedure. UseSELECT col INTO vVariablesyntax instead.
– slaakso
Nov 13 '18 at 12:23
add a comment |
When converting MS SQL Server procedures to MySQL procedures, you better use local variables declared with DECLARE.
The @var variables are user-defined variable and the scope is the process. So if your procedures call other procedures, the variable value may change whereas local variables will not. Local variables also have a defined type.
To convert MS SQL Server syntax
SELECT @MyParam = MyValue FROM MyTable
into MySQL, usee:
DECLARE vMyParam int;
SELECT MyValue INTO vMyParam FROM MyTable;
The format:
SELECT @MyParam := MyValue FROM MyTable
will cause an extra result set from the procedure so that is probably something you do not want.
You can use the := format when you use SET-command where you explicitly set a value for a variable.
SET vMyParam = 10;
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You need to use := operator instead of =, when you are assigning value to a user-defined variable in the SELECT clause. Former is assignment operator; while the latter is comparison operator.
SELECT @MyParam := MyValue FROM MyTable
However, if you are using SET clause, then you can use either = or :=. From docs:
For SET, either = or := can be used as the assignment operator.
More from the docs:
When making an assignment in this way (using
SELECT), you must use
:= as the assignment operator; = is treated as the comparison operator
in statements other than SET.
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
1
The:=format withSELCECTwill cause extra result set from the procedure. UseSELECT col INTO vVariablesyntax instead.
– slaakso
Nov 13 '18 at 12:23
add a comment |
You need to use := operator instead of =, when you are assigning value to a user-defined variable in the SELECT clause. Former is assignment operator; while the latter is comparison operator.
SELECT @MyParam := MyValue FROM MyTable
However, if you are using SET clause, then you can use either = or :=. From docs:
For SET, either = or := can be used as the assignment operator.
More from the docs:
When making an assignment in this way (using
SELECT), you must use
:= as the assignment operator; = is treated as the comparison operator
in statements other than SET.
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
1
The:=format withSELCECTwill cause extra result set from the procedure. UseSELECT col INTO vVariablesyntax instead.
– slaakso
Nov 13 '18 at 12:23
add a comment |
You need to use := operator instead of =, when you are assigning value to a user-defined variable in the SELECT clause. Former is assignment operator; while the latter is comparison operator.
SELECT @MyParam := MyValue FROM MyTable
However, if you are using SET clause, then you can use either = or :=. From docs:
For SET, either = or := can be used as the assignment operator.
More from the docs:
When making an assignment in this way (using
SELECT), you must use
:= as the assignment operator; = is treated as the comparison operator
in statements other than SET.
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
You need to use := operator instead of =, when you are assigning value to a user-defined variable in the SELECT clause. Former is assignment operator; while the latter is comparison operator.
SELECT @MyParam := MyValue FROM MyTable
However, if you are using SET clause, then you can use either = or :=. From docs:
For SET, either = or := can be used as the assignment operator.
More from the docs:
When making an assignment in this way (using
SELECT), you must use
:= as the assignment operator; = is treated as the comparison operator
in statements other than SET.
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
answered Nov 13 '18 at 10:46
Madhur BhaiyaMadhur Bhaiya
19.5k62236
19.5k62236
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
1
The:=format withSELCECTwill cause extra result set from the procedure. UseSELECT col INTO vVariablesyntax instead.
– slaakso
Nov 13 '18 at 12:23
add a comment |
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
1
The:=format withSELCECTwill cause extra result set from the procedure. UseSELECT col INTO vVariablesyntax instead.
– slaakso
Nov 13 '18 at 12:23
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
Excellent! That did the trick. I should have thought on this (though I'm MSSQL fan forced to move to MySQL..) Thx so much.
– Dave Gahan
Nov 13 '18 at 12:11
1
1
The
:= format with SELCECT will cause extra result set from the procedure. Use SELECT col INTO vVariable syntax instead.– slaakso
Nov 13 '18 at 12:23
The
:= format with SELCECT will cause extra result set from the procedure. Use SELECT col INTO vVariable syntax instead.– slaakso
Nov 13 '18 at 12:23
add a comment |
When converting MS SQL Server procedures to MySQL procedures, you better use local variables declared with DECLARE.
The @var variables are user-defined variable and the scope is the process. So if your procedures call other procedures, the variable value may change whereas local variables will not. Local variables also have a defined type.
To convert MS SQL Server syntax
SELECT @MyParam = MyValue FROM MyTable
into MySQL, usee:
DECLARE vMyParam int;
SELECT MyValue INTO vMyParam FROM MyTable;
The format:
SELECT @MyParam := MyValue FROM MyTable
will cause an extra result set from the procedure so that is probably something you do not want.
You can use the := format when you use SET-command where you explicitly set a value for a variable.
SET vMyParam = 10;
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
add a comment |
When converting MS SQL Server procedures to MySQL procedures, you better use local variables declared with DECLARE.
The @var variables are user-defined variable and the scope is the process. So if your procedures call other procedures, the variable value may change whereas local variables will not. Local variables also have a defined type.
To convert MS SQL Server syntax
SELECT @MyParam = MyValue FROM MyTable
into MySQL, usee:
DECLARE vMyParam int;
SELECT MyValue INTO vMyParam FROM MyTable;
The format:
SELECT @MyParam := MyValue FROM MyTable
will cause an extra result set from the procedure so that is probably something you do not want.
You can use the := format when you use SET-command where you explicitly set a value for a variable.
SET vMyParam = 10;
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
add a comment |
When converting MS SQL Server procedures to MySQL procedures, you better use local variables declared with DECLARE.
The @var variables are user-defined variable and the scope is the process. So if your procedures call other procedures, the variable value may change whereas local variables will not. Local variables also have a defined type.
To convert MS SQL Server syntax
SELECT @MyParam = MyValue FROM MyTable
into MySQL, usee:
DECLARE vMyParam int;
SELECT MyValue INTO vMyParam FROM MyTable;
The format:
SELECT @MyParam := MyValue FROM MyTable
will cause an extra result set from the procedure so that is probably something you do not want.
You can use the := format when you use SET-command where you explicitly set a value for a variable.
SET vMyParam = 10;
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
When converting MS SQL Server procedures to MySQL procedures, you better use local variables declared with DECLARE.
The @var variables are user-defined variable and the scope is the process. So if your procedures call other procedures, the variable value may change whereas local variables will not. Local variables also have a defined type.
To convert MS SQL Server syntax
SELECT @MyParam = MyValue FROM MyTable
into MySQL, usee:
DECLARE vMyParam int;
SELECT MyValue INTO vMyParam FROM MyTable;
The format:
SELECT @MyParam := MyValue FROM MyTable
will cause an extra result set from the procedure so that is probably something you do not want.
You can use the := format when you use SET-command where you explicitly set a value for a variable.
SET vMyParam = 10;
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
edited Nov 13 '18 at 12:28
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
answered Nov 13 '18 at 12:21
slaaksoslaakso
2,946818
2,946818
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
add a comment |
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
thanks for clarifying this. Just tested it and it worked perfectly. Thx
– Dave Gahan
Nov 13 '18 at 12:36
add a comment |
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